Literature summary for 1.13.11.B6 extracted from

Schiller, D.; Contreras, C.; Vogt, J.; Dunemann, F.; Defilippi, B.G.; Beaudry, R.; Schwab, W.
A dual positional specific lipoxygenase functions in the generation of flavor compounds during climacteric ripening of apple (2015), Hortic. Res., 2, 15003-15015 .

Search for more literature for 1.13.11.B6

Cloned(Commentary)

Cloned (Comment)	Organism
gene LOX1a, RT-PCR and real-time quantitative PCR expression analysis, 22 putative LOX genes in apple, gene expression analysis throughout ripening reveals that only six LOXs are expressed in a ripening-dependent manner, overview. DNA and amino acid sequence determination and analysis, recombinant expression of N-terminally His-tagged or untagged LOX genes endoing for isozymes LOX1:Md:1a, L, X1:Md:1c, LOX2:Md:2a, and LOX2:Md:2b, containing an enterokinase cleavage recognition site in the first case, in Saccharomyces cerevisiae strain INVSc1, recombinant expression of YFP-tagged enzyme	Malus domestica
gene LOX2a, RT-PCR and real-time quantitative PCR expression analysis, 22 putative LOX genes in apple, gene expression analysis throughout ripening reveals that only six LOXs are expressed in a ripening-dependent manner, overview. DNA and amino acid sequence determination and analysis, recombinant expression of N-terminally His-tagged or untagged LOX genes endoing for isozymes LOX1:Md:1a, L, X1:Md:1c, LOX2:Md:2a, and LOX2:Md:2b, containing an enterokinase cleavage recognition site in the first case, in Saccharomyces cerevisiae strain INVSc1, recombinant expression of YFP-tagged enzyme	Malus domestica

Cloned (Comment)

Organism

gene LOX1a, RT-PCR and real-time quantitative PCR expression analysis, 22 putative LOX genes in apple, gene expression analysis throughout ripening reveals that only six LOXs are expressed in a ripening-dependent manner, overview. DNA and amino acid sequence determination and analysis, recombinant expression of N-terminally His-tagged or untagged LOX genes endoing for isozymes LOX1:Md:1a, L, X1:Md:1c, LOX2:Md:2a, and LOX2:Md:2b, containing an enterokinase cleavage recognition site in the first case, in Saccharomyces cerevisiae strain INVSc1, recombinant expression of YFP-tagged enzyme

Malus domestica

gene LOX2a, RT-PCR and real-time quantitative PCR expression analysis, 22 putative LOX genes in apple, gene expression analysis throughout ripening reveals that only six LOXs are expressed in a ripening-dependent manner, overview. DNA and amino acid sequence determination and analysis, recombinant expression of N-terminally His-tagged or untagged LOX genes endoing for isozymes LOX1:Md:1a, L, X1:Md:1c, LOX2:Md:2a, and LOX2:Md:2b, containing an enterokinase cleavage recognition site in the first case, in Saccharomyces cerevisiae strain INVSc1, recombinant expression of YFP-tagged enzyme

Malus domestica

Protein Variants

Protein Variants	Comment	Organism
G567A	site-directed mutagenesis, the mutant converts the dual positional specific LOX1:Md:1a to an enzyme with a high specificity for 9(S)-hydroperoxide formation	Malus domestica
G567A	site-directed mutagenesis, the mutant converts the dual positional specific LOX1:Md:1a to an enzyme with a high specificity for 9(S)-hydroperoxide formation, mutant substrate specificity compared to the wild-type enzyme, chiral analysis	Malus domestica
I566F	site-directed mutagenesis, inactive mutant	Malus domestica
I578L	site-directed mutagenesis, mutant substrate specificity compared to the wild-type enzyme, chiral analysis	Malus domestica
L572I	site-directed mutagenesis, inactive mutant	Malus domestica
additional information	mutants Arg268Ala, Gly567Ala, Ile578Leu and Val582Phe show high substrate conversion rates of linoleate, linolenate and arachidonate (60%-100% of wild-type LOX1:Md:1a activity with linoleate). Substrate specificity of mutants, overview	Malus domestica
R268A	site-directed mutagenesis, mutant substrate specificity compared to the wild-type enzyme, chiral analysis	Malus domestica
V582F	site-directed mutagenesis, mutant substrate specificity compared to the wild-type enzyme, chiral analysis	Malus domestica

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
additional information	-	additional information	Michaelis-Menten kinetics	Malus domestica

Localization

Localization	Comment	Organism	GeneOntology No.	Textmining
additional information	not in chloroplasts	Malus domestica	-	-

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.
linoleate + O2	Malus domestica	-	(9R,10E,12Z)-9-hydroperoxy-10,12-octadecadienoate + (9Z,11E,13R)-13-hydroperoxy-9,11-octadecadienoate	-	?
linoleate + O2	Malus domestica	-	9-hydroperoxy-10,12-octadecadienoate + 13-hydroperoxy-9,11-octadecadienoate	-	?
linolenate + O2	Malus domestica	-	?	-	?

Organism

Organism	UniProt	Comment	Textmining
Malus domestica	S4UKU4	LOX2:Md:2a	-
Malus domestica	S4UL92	LOX1:Md:1a	-

Purification (Commentary)

Purification (Comment)	Organism
recombinant His-tagged enzymes from Saccharomyces cerevisiae strain INVSc1 by nickel affinity chromatographyand ultrafiltration	Malus domestica

Source Tissue

Source Tissue	Comment	Organism	Textmining
fruit	expression analysis of isozymes	Malus domestica	-
fruit	high expression level of isozyme MdLOX1a gene in stored apple fruit, expression analysis of isozymes	Malus domestica	-
additional information	no visible PCR bands from isozymes MdLOX1d, MdLOX4a, MdLOX5d, MdLOX5e and MdLOX9a during fruit development	Malus domestica	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.
linoleate + O2	-	Malus domestica	(9R,10E,12Z)-9-hydroperoxy-10,12-octadecadienoate + (9Z,11E,13R)-13-hydroperoxy-9,11-octadecadienoate	-	?
linoleate + O2	-	Malus domestica	9-hydroperoxy-10,12-octadecadienoate + 13-hydroperoxy-9,11-octadecadienoate	-	?
linolenate + O2	-	Malus domestica	?	-	?
additional information	regio- and stereospecificity analysis of isozyme substrate specificity, recombinant LOX1:Md:1a, LOX1:Md:1c, LOX2:Md:2a and LOX2:Md:2b isozymes show 13/9-LOX, 9-LOX, 13/9-LOX and 13-LOX activity with linoleic acid, respectively. While products of LOX1:Md:1c and LOX2:Md:2b are S-configured, LOX1:Md:1a and LOX2:Md:2a form 13(R)-hydroperoxides as major products. Oxygenation in the carbon backbone of linoleic acid occurs either at carbon atom 9 (9-LOX) or 13 (13-LOX), forming the corresponding hydroperoxy derivatives, respectively. LOX enzymes are not perfectly specific and biocatalysts that produce more than 10% of the alternative regio-isomer are called dual positional specific LOX	Malus domestica	?	-	?

Subunits

Subunits	Comment	Organism
?	x * 101500, recombinant His-tagged isozyme LOX1a, SDS-PAGE	Malus domestica
?	x * 106500, recombinant His-tagged isozyme LOX2a, SDS-PAGE	Malus domestica

Synonyms

Synonyms	Comment	Organism
dual positional specific LOX	-	Malus domestica
linoleate oxygen oxidoreductase	-	Malus domestica
lipoxygenase	-	Malus domestica
LOX	-	Malus domestica
LOX1:Md:1a	-	Malus domestica
LOX1a	-	Malus domestica
LOX2:Md:2a	-	Malus domestica
LOX2a	-	Malus domestica

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
35	-	-	Malus domestica
45	-	-	Malus domestica

Temperature Range [°C]

Temperature Minimum [°C]	Temperature Maximum [°C]	Comment	Organism
15	45	isozyme LOX2:Md:2a shows negligible activity at temperatures higher than 45°C	Malus domestica
15	55	isozyme LOX1:Md:1a shows a rather narrow optimum at 45°C with rapidly decreasing activity at lower or higher temperatures, but high residual activity at 55°C	Malus domestica

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
6	-	-	Malus domestica
7	-	-	Malus domestica

pH Range

pH Minimum	pH Maximum	Comment	Organism
4.5	8	over 60% of maxmal activity within this range	Malus domestica
5	7.5	over 80% of maximal activity in a broad pH range with sharply decreasing relative activity below pH 5.0 and above pH 7.5	Malus domestica

General Information

General Information	Comment	Organism
evolution	DNA and amino acid sequence determination and analysis of LOX1 and LOX2 isozymes, phylogenetic analysis, only LOX1:Md:1a exhibits a glycine residue (Gly567) responsible for dual positional specificity and (R)-LOX activity	Malus domestica
metabolism	the enzyme is involved in the LOX pathway, overview	Malus domestica
additional information	structure homology modeling	Malus domestica
physiological function	lipoxygenase (LOX) is an important contributor to the formation of aroma-active C6 aldehydes in apple (Malus3domestica) fruit upon tissue disruption, role in autonomously produced aroma volatiles from intact tissue, overview. The genetic association with a quantitative trait locus for fruit ester and the remarkable agreement in regio- and stereoselectivity of the LOX1:Md:1a reaction with the overall LOX activity found in mature apple fruits, suggest a major physiological function of LOX1:Md:1a during climacteric ripening of apples. While isozymes LOX1:Md:1c, LOX2:Md:2a, and LOX2:Md:2b may contribute to aldehyde production in immature fruit upon cell disruption isozyme, LOX1:Md:1a probably regulates the availability of precursors for ester production in intact fruit tissue. Both 9- and 13-hydroperoxides can be catabolized to aroma-active volatile aldehydes by hydroperoxide lyase. Only 13-LOX activity contributes to the apple aroma due to the formation of precursors of C6 volatile compounds. The dioxygenation of PUFAs by 9- and 13-LOX activity forms precursors for important phytooxylipins with functions in plant defense, wound signaling, senescence and fruit ripening	Malus domestica