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Information on EC 7.2.1.3 - ascorbate ferrireductase (transmembrane)
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7.2.1.3 ascorbate ferrireductase (transmembrane)IUBMB Comments
A diheme cytochrome that transfers electrons across a single membrane, such as the outer membrane of the enterocyte, or the tonoplast membrane of the plant cell vacuole. Acts on hexacyanoferrate(III) and other ferric chelates.
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Word Map
- 7.2.1.3
- photosystem
- hepcidin
-
ferroportin
- hephaestin
-
iron-deficient
-
fe-deficient
- beta-hydroxylase
- hemochromatosis
-
high-potential
- monodehydroascorbate
-
oxygen-evolving
-
extravesicular
- pheophytin
-
iron-related
-
calcareous
-
ascorbate-reducible
-
flash-induced
- semidehydroascorbate
-
alpha-bands
-
3-3,4-dichlorophenyl-1,1-dimethylurea
- ferroxidase
-
fe-sufficient
The enzyme appears in viruses and cellular organisms
Reaction Schemes
Synonyms
cytochrome b561, cytochrome b-559, dcytb, ferric chelate reductase, duodenal cytochrome b, cybrd1, cyt b561, cyb561, cyt-b561, lcytb, 
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SYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
ascorbate-cytochrome b5 reductase
-
-
-
-
ascorbate-dependent ferrireductase
CGCytb
chromaffin granule CYB561
chromaffin granule cytochrome b
CYB561
Cybrd1
Cyt b561
Cyt-b561
cytochrome b561
DCytb
duodenal cytochrome b
EC 1.10.2.1
-
-
formerly
-
EC 1.16.5.1
-
-
formerly
-
ferric reductase
LCytb
lysosomal cytochrome b
TCytb
cytochrome b561
-
-
ambiguous
-
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REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
-
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2]
reaction mechanism
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2]
reaction mechanism
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2]
reaction mechanism
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2]
reaction mechanism
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2]
reaction mechanism
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2]
reaction mechanism
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REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
oxidation
-
-
-
-
redox reaction
-
-
-
-
reduction
-
-
-
-
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SYSTEMATIC NAME
IUBMB Comments
Fe(III):ascorbate oxidorectuctase (electron-translocating)
A diheme cytochrome that transfers electrons across a single membrane, such as the outer membrane of the enterocyte, or the tonoplast membrane of the plant cell vacuole. Acts on hexacyanoferrate(III) and other ferric chelates.
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CAS REGISTRY NUMBER
COMMENTARY
37237-57-3
-
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SUBSTRATE
PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
ascorbate[side 1] + Fe3+-EDTA[side 2]
monodehydroascorbate[side 1] + Fe2+-EDTA[side 2]
-
compared with FeCN, Fe3+-EDTA is a relatively poor substrate for the enzyme (20-35fold lower ferrireductase activities)
-
-
?
ascorbate[side 1] + ferricyanide[side 2]
monodehydroascorbate[side 1] + ferrocyanide[side2]
-
-
-
-
-
ascorbate[side 1] + nitroblue tetrazolium[side 2]
dehydroascorbate + ?
-
-
-
-
?
bathocuprionedisulfonate[side 1] + Cu(II)-nitrilotriacetic acid[side 2]
Cu(I)-bathocuproinedisulfonate
-
-
-
-
?
ferrozine[side 1] + Fe(III)-nitrilotriacetic acid[side 2]
Fe(II)-ferrozine
-
-
-
-
?
ascorbate[side 1] + Fe(CN)3[side 2]
monodehydroascorbate[side 1] + ?
-
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
r
ascorbate[side 1] + Fe3+-EDTA[side 2]
monodehydroascorbate[side 1] + ?
-
-
-
-
?
ascorbate[side 1] + Fe3+-EDTA[side 2]
monodehydroascorbate[side 1] + ?
-
-
-
-
?
ascorbate[side 1] + Fe3+-EDTA[side 2]
monodehydroascorbate[side 1] + ?
-
-
-
-
?
L-(+)-ascorbate + ferricytochrome b5
monodehydro-L(+)-ascorbate + ferrocytochrome b5
-
-
-
-
?
L-(+)-ascorbate + ferricytochrome b5
monodehydro-L(+)-ascorbate + ferrocytochrome b5
-
the microsomal enzyme participates in the ascorbate-dependent fatty acid desaturation
-
-
?
L-ascorbate + ferricytochrome b5
monodehydro-L-ascorbate + ferrocytochrome b5
-
-
-
-
?
L-ascorbate + ferricytochrome b5
monodehydro-L-ascorbate + ferrocytochrome b5
-
-
-
-
?
L-ascorbate + ferricytochrome b5
monodehydro-L-ascorbate + ferrocytochrome b5
-
-
-
-
?
L-ascorbate + ferricytochrome b5
monodehydro-L-ascorbate + ferrocytochrome b5
-
-
-
-
?
L-ascorbate + ferricytochrome b5
monodehydroascorbate + ferrocytochrome b5 + H+
-
-
-
-
r
L-ascorbate + ferricytochrome b5
monodehydroascorbate + ferrocytochrome b5 + H+
-
-
-
-
r
additional information
?
-
structure-function relationship, overview
-
-
?
additional information
?
-
trans-membrane ferric reductase activity is also demonstrated in a reconstituted proteoliposome system with ascorbate as the electron donor inside the liposomes, recombinant CGCytb as trans-membrane electron carrier, and ferricyanide as the electron acceptor outside the liposomes. A few members of the CYB561 protein family function as ferric reductases in vivo. The other heme-b center is responsible for the ascorbate oxidation by iozyme CGCytb
-
-
?
additional information
?
-
enzyme assays also with purified chromaffin granule membrane ghosts, or purified proteins in detergent micelles, or in reconstituted membrane vesicles. Structure-function relationship, overview
-
-
?
additional information
?
-
the other heme-b center is responsible for the ascorbate oxidation by iozyme CGCytb. Structure-function relationship, overview
-
-
?
additional information
?
-
-
Dcytb has the capacity to reduce both iron and copper complexes
-
-
?
additional information
?
-
the other heme-b center is responsible for the ascorbate oxidation by iozyme CGCytb. Structure-function relationship, overview
-
-
?
additional information
?
-
structure-function relationship, overview
-
-
?
additional information
?
-
a few members of the CYB561 protein family function as ferric reductases in vivo
-
-
?
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NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
?
ascorbate[side 1] + Fe(III)[side 2]
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
-
-
r
L-(+)-ascorbate + ferricytochrome b5
monodehydro-L(+)-ascorbate + ferrocytochrome b5
-
-
-
-
?
L-(+)-ascorbate + ferricytochrome b5
monodehydro-L(+)-ascorbate + ferrocytochrome b5
-
the microsomal enzyme participates in the ascorbate-dependent fatty acid desaturation
-
-
?
additional information
?
-
trans-membrane ferric reductase activity is also demonstrated in a reconstituted proteoliposome system with ascorbate as the electron donor inside the liposomes, recombinant CGCytb as trans-membrane electron carrier, and ferricyanide as the electron acceptor outside the liposomes. A few members of the CYB561 protein family function as ferric reductases in vivo. The other heme-b center is responsible for the ascorbate oxidation by iozyme CGCytb
-
-
?
additional information
?
-
a few members of the CYB561 protein family function as ferric reductases in vivo
-
-
?
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COFACTOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
ascorbate
additions of ascorbate to oxidized wild-type Zmb561 and His6-tagged recombinant Zmb561 causes a quick reduction of heme b reaching the final reduction level of about 80%, suggesting that Zmb561 might utilize ascorbate as a physiological reductant in maize cells
ascorbate
cytosolic ascorbate is the cellular electron donor for the CYB561 proteins
ascorbate
cytosolic ascorbate is the cellular electron donor for the CYB561 proteins
ascorbate
cytosolic ascorbate is the cellular electron donor for the CYB561 proteins
ascorbate
cytosolic ascorbate is the cellular electron donor for the CYB561 proteins
ascorbate
cytosolic ascorbate is the cellular electron donor for the CYB561 proteins
ascorbate
cytosolic ascorbate is the cellular electron donor for the CYB561 proteins
heme
each monomer of the homodimeric protein possesses cytoplasmic and apical heme groups
heme b
cytosolic heme b prosthetic group, the transmembrane electron transport protein cytochromes b561 has two heme ligation sites
heme b
two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials of heme b, comparisons
heme b
two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons
heme b
two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons
heme b
two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons
heme b
two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons. The high-potential heme-b, characterized with a low-spin EPR signal in the vicinity of gz = 3.1, is located on the cytosolic side of the protein
heme b
two heme-b centers are coordinated by two pairs of His residues localized in the central four transmembrane domains, probably very close to the membrane interface. The midpoint redox potentials of the two hemes are above 0 mV and about 100 mV apart from each other. CYB561 protein structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons. The high-potential heme-b center of CGCytb is located on the cytosolic side of the protein, mutational analysis
additional information
neither ferrocyanide nor durohydroquinone can reduce nCGCytb
-
additional information
neither ferrocyanide nor durohydroquinone can reduce nCGCytb
-
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INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
diethylpyrocarbonate
-
the electron accepting ability of bovine cytochrome b561 from ascorbate is selectively inhibited by the treatment with diethylpyrocarbonate
Zn2+
1 mM, 43% residual activity. Zn2+ coordinates to two hydroxyl groups of the apical ascorbate and to a histidine residue. Fe3+ competes with Zn2+ for this binding site
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ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
ascorbate
-
cytb561 ferric reductase activity is greatly enhanced by the addition of ascorbate
dehydroascorbate
-
preloading cells with dehydroascorbate greatly increases both ferric and cupric reductase activities of Dcytb
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DISEASE
TITLE OF PUBLICATION
LINK TO PUBMED
Adenocarcinoma
Overexpression of cellular iron import proteins is associated with malignant progression of esophageal adenocarcinoma.
Anemia
Altered expression of intestinal duodenal cytochrome b and divalent metal transporter 1 might be associated with cardio-renal anemia syndrome.
Anemia
Fermented Goat's Milk Consumption Improves Duodenal Expression of Iron Homeostasis Genes during Anemia Recovery.
Anemia
Immunolocalization of duodenal cytochrome B: a relationship with circulating markers of iron status.
Anemia, Hypochromic
CIPK23 is involved in iron acquisition of Arabidopsis by affecting ferric chelate reductase activity.
Anemia, Hypochromic
Overexpression of AtFRO6 in transgenic tobacco enhances ferric chelate reductase activity in leaves and increases tolerance to iron-deficiency chlorosis.
Anemia, Sideroblastic
Recent advances in disorders of iron metabolism: mutations, mechanisms and modifiers.
ascorbate ferrireductase (transmembrane) deficiency
Congenital absence of norepinephrine due to CYB561 mutations.
Brain Diseases
Clonic seizures, continuous spikes-and-waves during slow sleep, choreoathetosis and response to sulthiame in a child with FRRS1L encephalopathy.
Brain Diseases
Loss of Frrs1l disrupts synaptic AMPA receptor function, and results in neurodevelopmental, motor, cognitive and electrographical abnormalities.
Breast Neoplasms
DCYTB is a predictor of outcome in breast cancer that functions via iron-independent mechanisms.
Carcinoma
Expression profiling of adrenocortical neoplasms suggests a molecular signature of malignancy.
Colorectal Neoplasms
A novel test for gene-ancestry interactions in genome-wide association data.
Colorectal Neoplasms
Duodenal cytochrome b (Cybrd1) ferric reductase functional studies in cells.
Fatty Liver
Association of mRNA expression of iron metabolism-associated genes and progression of non-alcoholic steatohepatitis in rats.
Friedreich Ataxia
Recent advances in disorders of iron metabolism: mutations, mechanisms and modifiers.
Glioblastoma
Highly Expressed CYBRD1 Associated with Glioma Recurrence Regulates the Immune Response of Glioma Cells to Interferon.
Glioblastoma
Mouse cytochrome b561: cDNA cloning and expression in rat brain, mouse embryos, and human glioma cell lines.
Glioma
Highly Expressed CYBRD1 Associated with Glioma Recurrence Regulates the Immune Response of Glioma Cells to Interferon.
Glioma
Mouse cytochrome b561: cDNA cloning and expression in rat brain, mouse embryos, and human glioma cell lines.
Hemochromatosis
A novel association between a SNP in CYBRD1 and serum ferritin levels in a cohort study of HFE hereditary haemochromatosis.
Hemochromatosis
Analysis of genes implicated in iron regulation in individuals presenting with primary iron overload.
Hemochromatosis
Analysis of polymorphism and hepatic expression of duodenal cytochrome b in chronic hepatitis C.
Hemochromatosis
Duodenal cytochrome b (Cybrd1) ferric reductase functional studies in cells.
Hemochromatosis
Duodenal cytochrome b and hephaestin expression in patients with iron deficiency and hemochromatosis.
Hemochromatosis
Duodenal Dcytb and hephaestin mRNA expression are not significantly modulated by variations in body iron homeostasis.
Hemochromatosis
Duodenal expression of iron transport molecules in untreated haemochromatosis subjects.
Hemochromatosis
Regulatory defects in liver and intestine implicate abnormal hepcidin and Cybrd1 expression in mouse hemochromatosis.
Hepatitis C, Chronic
Analysis of polymorphism and hepatic expression of duodenal cytochrome b in chronic hepatitis C.
Hypotension, Orthostatic
Mutations in CYB561 Causing a Novel Orthostatic Hypotension Syndrome.
Iron Deficiencies
CIPK23 is involved in iron acquisition of Arabidopsis by affecting ferric chelate reductase activity.
Iron Deficiencies
Cybrd1 (duodenal cytochrome b) is not necessary for dietary iron absorption in mice.
Iron Deficiencies
Differing expression of genes involved in non-transferrin iron transport across plasma membrane in various cell types under iron deficiency and excess.
Iron Deficiencies
Duodenal cytochrome b and hephaestin expression in patients with iron deficiency and hemochromatosis.
Iron Deficiencies
Duodenal Dcytb and hephaestin mRNA expression are not significantly modulated by variations in body iron homeostasis.
Iron Deficiencies
Duodenal Reductase Activity and Spleen Iron Stores Are Reduced and Erythropoiesis Is Abnormal in Dcytb Knockout Mice Exposed to Hypoxic Conditions.
Iron Deficiencies
FIT interacts with AtbHLH38 and AtbHLH39 in regulating iron uptake gene expression for iron homeostasis in Arabidopsis.
Iron Deficiencies
Gene expression profiling of Hfe-/- liver and duodenum in mouse strains with differing susceptibilities to iron loading: identification of transcriptional regulatory targets of Hfe and potential hemochromatosis modifiers.
Iron Deficiencies
High-fat diet causes iron deficiency via hepcidin-independent reduction of duodenal iron absorption.
Iron Deficiencies
Immunolocalization of duodenal cytochrome B: a relationship with circulating markers of iron status.
Iron Deficiencies
Intestinal hypoxia-inducible transcription factors are essential for iron absorption following iron deficiency.
Iron Deficiencies
Microbial siderophores exert a subtle role in Arabidopsis during infection by manipulating the immune response and the iron status.
Iron Deficiencies
Molecular and functional roles of duodenal cytochrome B (Dcytb) in iron metabolism.
Iron Deficiencies
Mutational reconstructed ferric chelate reductase confers enhanced tolerance in rice to iron deficiency in calcareous soil.
Iron Deficiencies
Nonclinical Characterization of the Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitor Roxadustat, a Novel Treatment of Anemia of Chronic Kidney Disease.
Iron Deficiencies
Overexpression of AtFRO6 in transgenic tobacco enhances ferric chelate reductase activity in leaves and increases tolerance to iron-deficiency chlorosis.
Iron Deficiencies
Overexpression of the FRO2 ferric chelate reductase confers tolerance to growth on low iron and uncovers posttranscriptional control.
Iron Deficiencies
Regulatory networks for the control of body iron homeostasis and their dysregulation in HFE mediated hemochromatosis.
Iron Deficiencies
Responses to iron deficiency in Arabidopsis thaliana: the Turbo iron reductase does not depend on the formation of root hairs and transfer cells.
Iron Deficiencies
The molecular circuitry regulating the switch between iron deficiency and overload in mice.
Iron Deficiencies
[Mutational reconstructed ferric chelate reductase confers enhanced tolerance in rice to iron deficiency in calcareous soil]
Iron Overload
Analysis of genes implicated in iron regulation in individuals presenting with primary iron overload.
Iron Overload
Analysis of polymorphism and hepatic expression of duodenal cytochrome b in chronic hepatitis C.
Iron Overload
Effect of lipopolysaccharide and bleeding on the expression of intestinal proteins involved in iron and haem transport.
Iron Overload
Iron overload in adult Hfe-deficient mice independent of changes in the steady-state expression of the duodenal iron transporters DMT1 and Ireg1/ferroportin.
Iron Overload
The molecular circuitry regulating the switch between iron deficiency and overload in mice.
Lymphoma, B-Cell
Genomic structure and expression of the human gene encoding cytochrome b561, an integral protein of the chromaffin granule membrane.
Neoplasm Metastasis
DCYTB is a predictor of outcome in breast cancer that functions via iron-independent mechanisms.
Neoplasms
DCYTB is a predictor of outcome in breast cancer that functions via iron-independent mechanisms.
Neoplasms
Electron Transfer Reactions of Candidate Tumor Suppressor 101F6 Protein, a Cytochrome b561 Homologue, with Ascorbate and Monodehydroascorbate Radical.
Neoplasms
Elevated expression of the cytochrome b561, a neuroendocrine vesicle protein, in castration resistant prostate tumors.
Neoplasms
Genomic structure and expression of the human gene encoding cytochrome b561, an integral protein of the chromaffin granule membrane.
Neoplasms
Highly Expressed CYBRD1 Associated with Glioma Recurrence Regulates the Immune Response of Glioma Cells to Interferon.
Neoplasms
Identification of potential genes in upper tract urothelial carcinoma using next-generation sequencing with bioinformatics and in vitro analyses.
Neoplasms
Overexpression of the natural antisense hypoxia-inducible factor-1alpha transcript is associated with malignant phaeochromocytoma/paraganglioma.
Neoplasms
Spectral characterization of the recombinant mouse tumor suppressor 101F6 protein.
Porphyria Cutanea Tarda
Iron homeostasis in porphyria cutanea tarda: mutation analysis of promoter regions of CP, CYBRD1, HAMP and SLC40A1.
Porphyrias
Iron homeostasis in porphyria cutanea tarda: mutation analysis of promoter regions of CP, CYBRD1, HAMP and SLC40A1.
Prostatic Neoplasms
Elevated expression of the cytochrome b561, a neuroendocrine vesicle protein, in castration resistant prostate tumors.
Urinary Bladder Neoplasms
Identification of potential genes in upper tract urothelial carcinoma using next-generation sequencing with bioinformatics and in vitro analyses.
Vitamin A Deficiency
Vitamin a modulates the expression of genes involved in iron bioavailability.
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KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
additional information
additional information
stopped-flow kinetic analysis at pH 5.0-7.0
-
0.0152
Cu(II)-nitrilotriacetic acid[side 2]
-
in 25 mM MOPS, 25 mM MES, 5.4 mM KCl, 5 mM glucose, 140 mM NaCl, 1.8 mM CaCl2, 0.8 mM MgCl2, pH 7.0, at 22°C
0.0231
Cu(II)-nitrilotriacetic acid[side 2]
-
in 25 mM MOPS, 25 mM MES, 5.4 mM KCl, 5 mM glucose, 140 mM NaCl, 1.8 mM CaCl2, 0.8 mM MgCl2, pH 7.0, at 37°C
0.0018
cytochrome b5
-
rat microsome cytochrome-b5, detergent preparation
-
0.0022
cytochrome b5
-
rabbit microsome cytochrome-b5, trypsin preparation
-
0.0025
cytochrome b5
-
pig microsome cytochrome-b5, detergent preparation
-
0.003
cytochrome b5
-
rabbit microsome cytochrome-b5, detergent preparation
-
0.074
Fe(III)-nitrilotriacetic acid[side 2]
-
in 25 mM MOPS, 25 mM MES, 5.4 mM KCl, 5 mM glucose, 140 mM NaCl, 1.8 mM CaCl2, 0.8 mM MgCl2, pH 7.0, at 37°C
0.0921
Fe(III)-nitrilotriacetic acid[side 2]
-
in 25 mM MOPS, 25 mM MES, 5.4 mM KCl, 5 mM glucose, 140 mM NaCl, 1.8 mM CaCl2, 0.8 mM MgCl2, pH 7.0, at 22°C
0.001
ferricytochrome b5
-
pig microsome cytochrome-b5, detergent preparation
0.001
ferricytochrome b5
-
long ferricytochrome b5 from pig microsomes, at pH 6.5 and 30°C
0.0014
ferricytochrome b5
-
rabbit microsome cytochrome-b5, detergent preparation
0.0014
ferricytochrome b5
-
rat microsome cytochrome-b5, detergent preparation
0.0014
ferricytochrome b5
-
long ferricytochrome b5 from rabbit microsomes, at pH 6.5 and 30°C
0.0016
ferricytochrome b5
-
rat microsome cytochrome-b5, trypsin preparation
0.0016
ferricytochrome b5
-
short ferricytochrome b5 from rat microsomes, at pH 6.5 and 30°C
0.0017
ferricytochrome b5
-
short ferricytochrome b5 from rabbit microsomes, at pH 6.5 and 30°C
0.0022
ferricytochrome b5
-
long ferricytochrome b5 from rabbit microsomes, at pH 6.5 and 30°C
0.0027
ferricytochrome b5
-
pig microsome cytochrome-b5, trypsin preparation
0.0027
ferricytochrome b5
-
short ferricytochrome b5 from pig microsomes, at pH 6.5 and 30°C
0.0028
ferricytochrome b5
-
short ferricytochrome b5 from pig microsomes, at pH 6.5 and 30°C
0.0037
ferricytochrome b5
-
long ferricytochrome b5 from rat microsomes, at pH 6.5 and 30°C
0.0038
ferricytochrome b5
-
rabbit microsome cytochrome-b5, trypsin preparation
0.0038
ferricytochrome b5
-
short ferricytochrome b5 from rabbit microsomes, at pH 6.5 and 30°C
0.004
ferricytochrome b5
-
short ferricytochrome b5 from rat microsomes, at pH 6.5 and 30°C
0.0048
ferricytochrome b5
-
long ferricytochrome b5 from pig microsomes, at pH 6.5 and 30°C
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SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
6.5
-
microsomes after CM-cellulose-chromatography, ultrafiltration and dialysis P2
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pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
7.4
additional information
additional information
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics
additional information
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics
additional information
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics
additional information
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics
additional information
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics
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ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
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SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SOURCE
-
chromaffin granule cytochrome b561 and lysosomal cytochrome b561
brenda
additional information
the parasitic trematode Schistosoma japonicum contains a CYB561 protein localized to the schistosome tegument
brenda
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LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
CGCytb, the chromaffin granule CYB561 of the mammalian adrenal glands (CGCytb) makes up about 10-15% of the adrenal gland chromaffin granule membrane proteins
brenda
CGCytb, the chromaffin granule CYB561 of the mammalian adrenal glands (CGCytb) makes up about 10-15% of the adrenal gland chromaffin granule membrane proteins
brenda
CGCytb, the chromaffin granule CYB561 of the mammalian adrenal glands (CGCytb) makes up about 10-15% of the adrenal gland chromaffin granule membrane proteins
brenda
a transmembrane enzyme, in the vacuolar (tonoplast) membrane. CYB561 proteins have six trans-membrane helices and two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling
brenda
a transmembrane enzyme, localization of both the N- and C-termini of CGCytb in the cytoplasm. Native CGCytb is a trans-membrane electron transferring protein that has 6 transmembrane domains with two pairs of His residues, arranged on four consecutive transmembrane domains (the CYB561-core), for coordinating two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling
brenda
a transmembrane enzyme, localization of both the N- and C-termini of CGCytb in the cytoplasm. Native CGCytb is a transmembrane electron transferring protein that has 6 transmembrane domains with two pairs of His residues, arranged on four consecutive transmembrane domains (the CYB561-core), for coordinating two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling
brenda
a transmembrane enzyme, localization of both the N- and C-termini of CGCytb in the cytoplasm. Native CGCytb is a transmembrane electron transferring protein that has 6 transmembrane domains with two pairs of His residues, arranged on four consecutive transmembrane domains (the CYB561-core), for coordinating two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling
brenda
a transmembrane enzyme, CYB561 proteins have six trans-membrane helices and two b-type hemes, one on each side of the membrane
brenda
a transmembrane enzyme, in the vacuolar (tonoplast) membrane. CYB561 proteins have six transmembrane helices and two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling
brenda
-
enzyme localizes to the plasma mebrane in transgenic Arabidopsis thaliana and Xenopus laevis oocyte
brenda
-
highly expressed in the brush-border membrane of duodenal enterocytes
brenda
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GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
evolution
malfunction
metabolism
physiological function
additional information
malfunction
mutation of His residues coordinating the intra-vesicular-side heme-b results in an almost complete loss of protein, while mutation of His residues coordinating the cytosolic-side heme-b hardly affects the expression of CYB561 proteins but results in a changed reducibility and heme content of these proteins
malfunction
mutation of His residues coordinating the intra-vesicular-side heme-b results in an almost complete loss of protein, while mutation of His residues coordinating the cytosolic-side heme-b hardly affects the expression of CYB561 proteins but results in a changed reducibility and heme content of these proteins. Replacing any of the 4 highly conserved His residues, coordinating the two b-type hemes, by Ala in mouse rLCytb completely abolishes the transmembrane ferric reductase activity of rLCytb
metabolism
enzyme is reduced by dihydrolipoic acid almost as efficiently as by ascorbate
metabolism
enzyme is reduced by dihydrolipoic acid almost as efficiently as by ascorbate
physiological function
-
Dcytb plays a physiological role in both iron and copper uptake, through divalent metal transporter1 and copper transporter 1, respectively
physiological function
b-Type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport
physiological function
b-type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. Isozyme DCytb is capable of reducing ferric chelates and plays an important role in the iron acquisition of cells
physiological function
b-type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. Isozyme DCytb is capable of reducing ferric chelates and plays an important role in the iron acquisition of cells
physiological function
b-Type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. Plant rTCytb are capable of transporting electrons from cytosolic ASC to extracellular ferric chelates (ferricyanide, ferric-EDTA) in a yeast model system
physiological function
b-Type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. Plant rTCytb are capable of transporting electrons from cytosolic ASC to extracellular ferric chelates (ferricyanide, ferric-EDTA) in a yeast model system
physiological function
b-Type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. The parasitic trematode Schistosoma japonicum contains a CYB561 protein with ferric chelate reductase activity and localizes to the schistosome tegument, the enzyme might be responsible for iron acquisition in the parasite
physiological function
cytochrome b561 exists in the neurosecretory vesicle membranes of the nervous system of higher animals. The cytochrome receives an electron equivalent from cytosolic ascorbate (AsA)1 and donates it to the intravesicular monodehydroascorbate radical to regenerate AsA after the transmembrane electron transfer. Transmembrane electron transfer catalyzed by cytochrome b561 is essential for the biosynthesis of neurotransmitters
physiological function
-
in transgenic CYBDOM complementary RNA-injected Xenopus laevis oocytes, CYBDOM-mediated currents are activated by extracellular electron acceptors in a concentration- and type-specific manner. Current amplitudes are voltage dependent and strongly potentiated in oocytes preinjected with ascorbate
additional information
conserved Lys83 residue in a cytosolic loop plays a very important role for the binding of ascorbate and the succeeding electron transfer via electrostatic interactions. Lys83 might also be responsible for the intramolecular electron transfer to the intravesicular heme. Conserved residues Ser118 and Trp122, located in the putative monodehydroascorbate radical binding site, do not have major roles for the redox events on the intravesicular side
additional information
cytochrome b561 (CYB561) proteins are ascorbate reducible, transmembrane proteins consisting of 200-300 amino acids, about half of which are hydrophobic. CYB561 proteins have six transmembrane helices and two b-type hemes, one on each side of the membrane. The two heme-b centers are coordinated by two pairs of His residues localized in the central four transmembrane domains, probably very close to the membrane interface. The midpoint redox potentials of the two hemes are above 0 mV and about 100 mV apart from each other. The binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that are inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview. Importance of an Arg residue in the reduction of rCGCytb
additional information
the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that are inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview
additional information
the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that had been inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview
additional information
the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that had been inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview. Importance of an Arg residue in the reduction of rCGCytb
additional information
the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that had been inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview. Importance of an Arg residue in the reduction of rCGCytb
additional information
the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that had been inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview. The amino acid side chains contributing to the docking of ascorbate on the cytoplasmic surface of the crystallized protein (K77, K81, Y140, R150 and A151) do not constitute a single contiguous region but originate at distant locations of the primary sequence of the protein
Show AA Sequence and Transmembrane Helices (2731 entries)
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MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
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SUBUNIT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
additional information
additional information
Cytb561 enzyme structure analysis, structure-function relationship, detailed overview
additional information
Cytb561 enzyme structure analysis, structure-function relationship, detailed overview
additional information
Cytb561 enzyme structure analysis, structure-function relationship, detailed overview
additional information
Cytb561 enzyme structure analysis, structure-function relationship, detailed overview
additional information
Cytb561 enzyme structure analysis, structure-function relationship, detailed overview
additional information
Cytb561 enzyme structure analysis, structure-function relationship, detailed overview
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POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
acetylation
the N-terminus of isozyme CBCytB is anchored to the membrane by acetylation of the amino-terminal Met residue
no glycoprotein
although the deduced amino acid sequence of Zmb561 contains two potential N-glycosylation sites (109NES111 and 203NFT205), periodic acid-Schiff staining of the purified wild-type-Zmb561 in SDS-PAGE gels do not show any indication of glycosyl groups
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CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
high-resolution crystal structures of cytochrome b561 from Arabidopsis thaliana in both substrate-free and substrate-bound states is reported. Cyt b561 forms a homodimer, with each protomer consisting of six transmembrane helices and two heme groups
enzyme and its complex with ascorbate and Zn2+. Each monomer of the homodimeric protein possesses cytoplasmic and apical heme groups, as well as cytoplasmic and apical ascorbate-binding sites located adjacent to each heme. Zn2+ coordinates to two hydroxyl groups of the apical ascorbate and to a histidine residue. Fe3+ competes with Zn2+ for this binding site
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PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
F105W/H106E
mutations on the noncytoplasmic side only still allows the oxidized Cyt b561 to be reduced by ascorbate
H117A
site-directed mutagenesis, the mutation leads to reduced reduction of ascorbate by the mutant TCytb
H156A
site-directed mutagenesis, the mutation leads to reduced reduction of ascorbate by the mutant TCytb
H50A
site-directed mutagenesis, the mutation leads to reduced reduction of ascorbate by the mutant TCytb
H83A
site-directed mutagenesis, the mutation leads to reduced reduction of ascorbate by the mutant TCytb
K81A/R150A
mutations on the cytoplasmic side only still allows the oxidized Cyt b561 to be reduced by ascorbate
K81A/R150A/F105W/H106E
Y115W
mutations on the noncytoplasmic side only still allows the oxidized Cyt b561 to be reduced by ascorbate
Y140W
mutations on the cytoplasmic side only still allows the oxidized Cyt b561 to be reduced by ascorbate
E79A
site-directed mutagenesis, the mutation in bovine rCGCytb causes significant (but no extreme) alteration in at least one of the two (sometimes three) midpoint ascorbate concentrations characterizing the redox transition of hemes-b, and the mutation does not block the reduction of either heme-b center
N78K
site-directed mutagenesis, the mutation in bovine rCGCytb does not influence the physicochemical properties of protein as compared to the wild-type
T84A
site-directed mutagenesis, the mutation in bovine rCGCytb causes significant (but no extreme) alteration in at least one of the two (sometimes three) midpoint ascorbate concentrations characterizing the redox transition of hemes-b, and the mutation does not block the reduction of either heme-b center
H120A
site-directed mutagenesis of DCytb, the mutation results in partial loss of hemes
H159A
site-directed mutagenesis of DCytb, the mutation results in partial loss of hemes
H33A
site-directed mutagenesis, mutation in human DCytb does not influence the physicochemical properties of protein as compared to the wild-type
H50A
site-directed mutagenesis of DCytb, the mutation results in complete loss of hemes
H50A/H120A
site-directed mutagenesis of DCytb, the mutant contains one heme-b per double His-mutant rDCytb
H86A
site-directed mutagenesis of DCytb, the mutation results in complete loss of hemes
H86A/H159A
site-directed mutagenesis of DCytb, the mutant contains one heme-b per double His-mutant rDCytb
D38A
E117A
-
the mutant shows decreased Fe(CN)3 reductase activity compared to the wild type enzyme
E177A
-
the mutation of lysosomal cytochrome b561 reduces the enzyme activity compared to the wild type
E196A
F44A
H105A
H108A
site-directed mutagenesis, the mutation results in a practically unchanged level of protein expression and a considerably lower ascorbate reducibility
H112A
H117A
H120A
site-directed mutagenesis, the mutation results in nearly undetectable levels of rCGCytb
H156A
H159A
site-directed mutagenesis, the mutation results in a practically unchanged level of protein expression and a considerably lower ascorbate reducibility
H47A
H52A
site-directed mutagenesis, the mutation results in nearly undetectable levels of rCGCytb
H83A
H86A
site-directed mutagenesis, the mutation results in a practically unchanged level of protein expression and a considerably lower ascorbate reducibility
H86A/H159A
site-directed mutagenesis, the mutation results in a practically unchanged level of protein expression and a considerably lower ascorbate reducibility
M51A
N106A
P48A
Q131A
R149A
R67A
R72A
site-directed mutagenesis, the mutant shows reduced activity compared to wild-type
R72E
R72K
site-directed mutagenesis, the mutant shows reduced activity compared to wild-type
R72T
site-directed mutagenesis, the mutant shows reduced activity compared to wild-type
R72Y
site-directed mutagenesis, the mutant shows reduced activity compared to wild-type
S115A
S118A
-
the mutation of lysosomal cytochrome b561 increases the enzyme activity compared to the wild type
W119A
Y190A
Y66A
K83A
K83D
K83E
S118A
W122A
additional information
replacing any of the 4 highly conserved His residues, coordinating the two b-type hemes, by Ala in mouse rLCytb completely abolishes the transmembrane ferric reductase activity of rLCytb. Midpoint ascorbate concentration for the reduction of low-potential heme-b centers is hardly influenced by the R74X replacements but that for the high-potential heme-b centers show a significant trend
K81A/R150A/F105W/H106E
mutant carrying ascorbate-binding mutations on both cytoplasmic and noncytoplasmic sides, completely loses its ability to be reduced by ascorbate
K81A/R150A/F105W/H106E
site-directed mutagenesis, the quadruple mutation completely prevents ascorbate from reducing the protein, inactive mutant
D38A
-
the mutant shows increased Fe(CN)3 reductase activity compared to the wild type enzyme
D38A
-
the mutation of lysosomal cytochrome b561 increases the enzyme activity compared to the wild type
E196A
-
the mutant shows decreased Fe(CN)3 reductase activity compared to the wild type enzyme
E196A
-
the mutation of lysosomal cytochrome b561 strongly reduces the enzyme activity compared to the wild type
F44A
-
the mutation of lysosomal cytochrome b561 reduces the enzyme activity by about 45% compared to the wild type
H105A
-
the mutant shows increased Fe(CN)3 reductase activity compared to the wild type enzyme
H105A
-
the mutation of lysosomal cytochrome b561 increases the enzyme activity compared to the wild type
H112A
-
the mutant shows decreased Fe(CN)3 reductase activity compared to the wild type enzyme
H112A
-
the mutation of lysosomal cytochrome b561 reduces the enzyme activity compared to the wild type
H117A
-
the mutation completely abrogates the Fe(CN)3 reductase activity of the enzyme
H117A
-
the mutation of lysosomal cytochrome b561 completely abrogates the FeCN reductase activity of the enzyme
H156A
-
the mutation completely abrogates the Fe(CN)3 reductase activity of the enzyme
H156A
-
the mutation of lysosomal cytochrome b561 completely abrogates the FeCN reductase activity of the enzyme
H47A
-
the mutation completely abrogates the Fe(CN)3 reductase activity of the enzyme
H47A
-
the mutation of lysosomal cytochrome b561 completely abrogates the FeCN reductase activity of the enzyme
H83A
-
the mutation completely abrogates the Fe(CN)3 reductase activity of the enzyme
H83A
site-directed mutagenesis, no alteration is found from the ascorbate reducibility compared to mouse wild-type rCGCytb
H83A
-
the mutation of lysosomal cytochrome b561 completely abrogates the FeCN reductase activity of the enzyme
M51A
-
the mutant shows increased Fe(CN)3 reductase activity compared to the wild type enzyme
M51A
-
the mutation of lysosomal cytochrome b561 increases the enzyme activity compared to the wild type
N106A
-
the mutant shows increased Fe(CN)3 reductase activity compared to the wild type enzyme
N106A
-
the mutation of lysosomal cytochrome b561 increases the enzyme activity compared to the wild type
P48A
-
the mutant shows increased reductase activity compared to the wild type enzyme
P48A
-
the mutation of lysosomal cytochrome b561 increases the enzyme activity compared to the wild type
Q131A
-
the activity of the mutant is reduced significantly to 45% of that of the wild type
Q131A
-
the mutation of lysosomal cytochrome b561 reduces the enzyme activity to 45% of that of the wild type
R149A
-
the mutation results in a 75% loss in activity compared to the wild type enzyme
R149A
-
the mutation of lysosomal cytochrome b561 results in a 75% loss in activity compared to the wild type enzyme
R67A
-
the mutation results in an almost complete loss of the Fe(CN)3 reductase activity
R67A
-
the mutation of lysosomal cytochrome b561 results in an almost complete loss of the FeCN reductase activity of the enzyme
R72E
site-directed mutagenesis, the mutant shows reduced activity compared to wild-type
R72E
site-directed mutagenesis, the mutation of TCytb does not affect the final reduction level of rTCytb by ascorbate but results in a complete loss of the pH-dependent initial time-lag upon electron acceptance from ascorbate
S115A
-
the ferrireductase activity of lysosomal cytochrome b561 in mutant S115A is reduced to 50% compared to the wild type
W119A
-
the mutant shows decreased Fe(CN)3 reductase activity compared to the wild type enzyme
W119A
-
the ferrireductase activity of lysosomal cytochrome b561 in mutant W119A is reduced to 17% compared to the wild type
Y190A
-
the mutant shows increased Fe(CN)3 reductase activity compared to the wild type enzyme
Y190A
-
the mutation of lysosomal cytochrome b561 increases the enzyme activity compared to the wild type
Y66A
-
the mutation results in an almost complete loss of the Fe(CN)3 reductase activity
Y66A
-
the mutation of lysosomal cytochrome b561 results in an almost complete loss of the FeCN reductase activity of the enzyme
K83A
site-directed mutagenesis, mutation of a cytosolic loop residue, the mutant shows a significant decrease in the final heme reduction level in an acidic pH region
K83A
site-directed mutagenesis, the mutant shows reduced ascorbate reducibility compared to wild-type
K83D
site-directed mutagenesis, mutation of a cytosolic loop residue, mutant K83D shows a significant reduction in the electron-accepting activity with ascorbate as reductant
K83D
site-directed mutagenesis, the mutant shows reduced ascorbate reducibility compared to wild-type
K83E
site-directed mutagenesis, mutation of a cytosolic loop residue, the mutant activity is similar to the wild-type enzyme
K83E
site-directed mutagenesis, the mutant shows reduced ascorbate reducibility compared to wild-type
S118A
site-directed mutagenesis, mutation in maize TCytb does not influence the physicochemical properties of protein as compared to the wild-type
S118A
site-directed mutagenesis, mutation of a conserved residue in the putative monodehydroascorbate radical binding site, the mutant electron transfer activity to the monodehydroascorbate radical is very similar to those of the wild-type protein, about 70% heme reduction level compared to wild-type
W122A
site-directed mutagenesis, mutation in maize TCytb does not influence the physicochemical properties of protein as compared to the wild-type
W122A
site-directed mutagenesis, mutation of a conserved residue in the putative monodehydroascorbate radical binding site, the mutant electron transfer activity to the monodehydroascorbate radical is very similar to those of the wild-type protein, about 70% heme reduction level compared to wild-type
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TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
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GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
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STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
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PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
native chromaffin granule CYB561 from adrenal gland from the chromaffin granule membrane by Triton X-100 solubilzation and separation of the solubilized nCGCytb by preparative electrophoresis. Recombinant C-terminaly His6-tagged isozyme CGCytb from Spodoptera frugiperda Sf9 cells, Pichia pastoris strain GS115, or Escherichia coli by nickel affinity chromatography to homogeneity
native enzyme from microsomal membranes by anion exchange and concanavalin A affinity chromatography, recombinant His6-tagged enzyme from Pichia pastoris by anion exchange and nickel affinity chromatography and gel filtration, elution with a solution containing 1.0% w/v n-octyl beta-glucoside
recombinant C-terminally His6-tagged isozyme DCytb from Spodoptera frugiperda Sf9 cells, and untagged, apoform or fully functional isozyme DCytb from Escherichia coli, to homogeneity
recombinant C-terminaly His6-tagged enzyme from yeast YPH499 cells by nickel affinity chromatography, recombinant C-terminally His6-tagged isozyme DCytb from Escherichia coli
recombinant untagged four CYB561 isoforms from yeast YPH499 cells partially, two recombinant C-terminally His10- or Strep-II-tagged CYB561 paralogues from Escherichia coli and Pichia pastoris by affinity chromatography
using Ni-NTA chromatography
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CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
cloning and recombinant expression of untagged four CYB561 isoforms in yeast YPH499 cells, recombinant expression of two C-terminally His10- or Strep-II-tagged CYB561 paralogues in either Escherichia coli or in Pichia pastoris. Functional expression of the enzyme in Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 deficient in ferric reductase activity
expressed as a His-tagged fusion protein in Escherichia coli
expressed in a Saccharomyces cerevisiae DELTAfre1DELTAfre2 mutant, which lacks almost all of its plasma membrane ferrireductase activity
-
expressed in a Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 mutant, which lacks almost all of its plasma membrane ferrireductase activity
expressed in the Saccharomyces cerevisiae mutant strain S288C DELTAfre1DELTAfre2 that lacks plasma membrane ferrireductase activity
-
functional expression of the enzyme in Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 deficient in ferric reductase activity
functional expression of the enzyme in Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 which is deficient in ferric reductase activity
recombinant expression of C-terminally His6-tagged isozyme CGCytb in Spodoptera frugiperda Sf9 cells as well as in Pichia pastoris strain GS115, and recombinant expression of C-terminally His6-tagged isozyme CGCytb in Escherichia coli
recombinant expression of C-terminally His6-tagged isozyme DCytb in Spodoptera frugiperda Sf9 cells, untagged, apoform or fully functional isozyme DCytb in Escherichia coli
recombinant expression of C-terminaly His6-tagged enzyme in yeast YPH499 cells, recombinant expression of C-terminally His6-tagged isozyme DCytb in Escherichia coli
recombinant expression of His6-tagged enzyme in Pichia pastoris under control of a methanol-inducible promoter AOX1
expressed in a Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 mutant, which lacks almost all of its plasma membrane ferrireductase activity
-
expressed in a Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 mutant, which lacks almost all of its plasma membrane ferrireductase activity
-
expressed in a Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 mutant, which lacks almost all of its plasma membrane ferrireductase activity
-
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EXPRESSION
ORGANISM
UNIPROT
LITERATURE
iron-deficient patients have significantly higher ferric reductase activity and duodenal and plasma ascorbate concentrations than do control subjects
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REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Everling, F.B.; Weis, W.; Staudinger, H.
Kinetische Untersuchungen an einer Ascorbat:Ferricytochrom-b5-oxydoreduktase (EC1.1.2.?)
Hoppe-Seyler's Z. Physiol. Chem.
350
S.1485-1492
1969
Rattus norvegicus
brenda
Weber, H.; Weis, W.; Staudinger, H.
Praeparative Untersuchungen and der mikrosomalen Ascorbat:Fericytochrom-b5-oxidoreduktase (EC1.10.2.1)
Hoppe-Seyler's Z. Physiol. Chem.
353
S.1415-1419
1972
Rattus norvegicus
brenda
Weber, H.; Weis, W.; Schaeg, W.; Staudinger, H.
Unterschiedliche Cytochrom-b5-Formen als Substrate fuer die L-ascorbat:ferricytochrom-b5-oxidoreduktase (EC1.10.2.1) aus Saeugetierlebermikrosomen
Hoppe-Seyler's Z. Physiol. Chem.
354
S.1277-1284
1973
Oryctolagus cuniculus, Rattus norvegicus, Sus scrofa
brenda
Scherer, G.; Weber, H.; Weis, W.
Trgergebundenes Cytochrom b5 als Substrat fuer die Ascorbat:Ferricytochrom-b5-oxidoreduktase aus Saeugetierlebermikrosomen
Hoppe-Seyler's Z. Physiol. Chem.
355
S.1350-1354
1974
Sus scrofa
brenda
Weber, H.; Weis, W.; Wolf, B.
Monodehydro-L(+)-ascorbat reduzierende Systeme in unterschiedlich praeparierten Schweinelebermikrosomen
Hoppe-Seyler's Z. Physiol. Chem.
355
S.595-599
1974
Sus scrofa
brenda
Wolf, B.; Weis, W.
Discrimination between ascorbate:ferricytochrome b5 oxidoreductase and the cyanide-sensitive factor of acyl-CoA desaturase
Biochem. Biophys. Res. Commun.
72
190-194
1976
Rattus norvegicus
brenda
Scherer, G.; Weis, W.
Partial purification of L-ascorbate:ferricytochrome b5 oxidoreductase from rat liver microsomes
Hoppe-Seyler's Z. Physiol. Chem.
358
S.1499-1503
1977
Rattus norvegicus
brenda
Scherer, G.; Weis, W.
Participation of L-ascorbate:ferricytochrome b5 oxidoreductase in ascorbate-dependent fatty acid desaturation of rat liver microsomes
Hoppe-Seyler's Z. Physiol. Chem.
359
S.1527-1530
1978
Rattus norvegicus
-
brenda
Knoepfel, M.; Solioz, M.
Characterization of a cytochrome b558 ferric/cupric reductase from rabbit duodenal brush border membranes
Biochem. Biophys. Res. Commun.
291
220-225
2002
Oryctolagus cuniculus, Mus musculus
brenda
Su, D.; Asard, H.
Three mammalian cytochromes b561 are ascorbate-dependent ferrireductases
FEBS J.
273
3722-3734
2006
Homo sapiens, Mus musculus, Rattus norvegicus
brenda
Atanasova, B.D.; Li, A.C.; Bjarnason, I.; Tzatchev, K.N.; Simpson, R.J.
Duodenal ascorbate and ferric reductase in human iron deficiency
Am. J. Clin. Nutr.
81
130-133
2005
Homo sapiens
brenda
Berczi, A.; Su, D.; Asard, H.
An Arabidopsis cytochrome b561 with trans-membrane ferrireductase capability
FEBS Lett.
581
1505-1508
2007
Arabidopsis thaliana
brenda
Wyman, S.; Simpson, R.J.; McKie, A.T.; Sharp, P.A.
Dcytb (Cybrd1) functions as both a ferric and a cupric reductase in vitro
FEBS Lett.
582
1901-1906
2008
Mus musculus
brenda
Nakanishi, N.; Takeuchi, F.; Tsubaki, M.
Histidine cycle mechanism for the concerted proton/electron transfer from ascorbate to the cytosolic haem b centre of cytochrome b561: a unique machinery for the biological transmembrane electron transfer
J. Biochem.
142
553-560
2007
Bos taurus
brenda
Glanfield, A.; McManus, D.P.; Smyth, D.J.; Lovas, E.M.; Loukas, A.; Gobert, G.N.; Jones, M.K.
A cytochrome b561 with ferric reductase activity from the parasitic blood fluke, Schistosoma japonicum
PLoS Negl. Trop. Dis.
4
e884
2010
Schistosoma japonicum
brenda
McKie, A.T.; Barrow, D.; Latunde-Dada, G.O.; Rolfs, A.; Sager, G.; Mudaly, E.; Mudaly, M.; Richardson, C.; Barlow, D.; Bomford, A.; Peters, T.J.; Raja, K.B.; Shirali, S.; Hediger, M.A.; Farzaneh, F.; Simpson, R.J.
An iron-regulated ferric reductase associated with the absorption of dietary iron
Science
291
1755-1759
2001
Mus musculus
brenda
Berczi, A.; Zimanyi, L.; Asard, H.
Dihydrolipoic acid reduces cytochrome b561 proteins
Eur. Biophys. J.
42
159-168
2013
Arabidopsis thaliana (Q8L856), Mus musculus (Q9WUE3)
brenda
Lu, P.; Ma, D.; Yan, C.; Gong, X.; Du, M.; Shi, Y.
Structure and mechanism of a eukaryotic transmembrane ascorbate-dependent oxidoreductase
Proc. Natl. Acad. Sci. USA
111
1813-1818
2014
Arabidopsis thaliana (Q9SWS1), Arabidopsis thaliana
brenda
Nakanishi, N.; Rahman, M.M.; Sakamoto, Y.; Takigami, T.; Kobayashi, K.; Hori, H.; Hase, T.; Park, S.-Y.; Tsubaki, M.
Importance of the conserved lysine 83 residue of Zea mays cytochrome b561 for ascorbate-specific transmembrane electron transfer as revealed by site-directed mutagenesis studies
Biochemistry
48
10665-10678
2009
Zea mays (Q5D8X4)
-
brenda
Berczi, A.; Zimanyi, L.
The trans-membrane cytochrome b561 proteins structural information and biological function
Curr. Protein Pept. Sci.
15
745-760
2014
Bos taurus (P10897), Homo sapiens (P49447), Schistosoma japonicum (Q5D8X4), Zea mays (Q6I681), Mus musculus (Q6P1H1), Arabidopsis thaliana (Q9SWS1)
brenda
Ganasen, M.; Togashi, H.; Takeda, H.; Asakura, H.; Tosha, T.; Yamashita, K.; Hirata, K.; Nariai, Y.; Urano, T.; Yuan, X.; Hamza, I.; Mauk, A.G.; Shiro, Y.; Sugimotom, H.; Sawai, H.
Structural basis for promotion of duodenal iron absorption by enteric ferric reductase with ascorbate
Commun. Biol.
1
120
2018
Homo sapiens (Q53TN4), Homo sapiens
brenda
Picco, C.; Scholz-Starke, J.; Festa, M.; Costa, A.; Sparla, F.; Trost, P.; Carpaneto, A.
Direct recording of trans-plasma membrane electron currents mediated by a member of the cytochrome b561 family of soybean
Plant Physiol.
169
986-995
2015
Glycine max
brenda
Su D., Asard H.
Three mammalian cytochromes b561 are ascorbate-dependent ferrireductases
FEBS J.
273
3722-3374
2006
Mus musculus
brenda
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