Cloned (Comment) | Organism |
---|---|
recombinant expression of N-terminally V5-tagged and C-terminally Myc-tagged enzyme in the murine fibroblast cell line LM-TK-, the enzyme co-localizes with the Golgi marker alpha-mannosidase II, and cytosolic and luminal orientation of N- and C-terminus, respectively, recombinant expression of a soluble secreted form of CASD1, which encompasses the SGNH-like luminal domain and a C-terminal Myc-His6-tag, in Spodoptera frugiperda SF9 cells via baculovirus transfection | Homo sapiens |
Protein Variants | Comment | Organism |
---|---|---|
additional information | CASD1 knockout abolishes Sia O-acetylation in HAP1 cells. Transfection with CASD1 cDNA, but not empty vector, results in successful complementation of the loss-of-function defect and restored 9-O-acetylation of Golgi-localized sialoglycotopes | Homo sapiens |
S94A | site-directed mutagenesis, inactive mutant | Homo sapiens |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
Golgi membrane | the enzyme is a multimembrane spanning protein with 13 transmembrane segments, the SGNH-like domain of CASD1 faces the Golgi lumen. The enzyme shows cytosolic and luminal orientation of its N- and C-terminus, respectively | Homo sapiens | 139 | - |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
acetyl-CoA + CMP-N-acetylneuraminate | Homo sapiens | - |
CoA + N-acetyl-9-O-acetylneuraminate + CMP | - |
? | |
additional information | Homo sapiens | enzyme CASD1 mediates 9-O-acetylation of cellular sialoglycans and sialoglycoconjugates | ? | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | Q96PB1 | - |
- |
Posttranslational Modification | Comment | Organism |
---|---|---|
glycoprotein | the soluble recombinant enzyme CASD1 expressed in Sf9 cells is N-glycosylated at the catalytic residue S94, the recombinant enzyme is therefore inactive | Homo sapiens |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
HAP-1 cell | - |
Homo sapiens | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
acetyl-CoA + CMP-N-acetylneuraminate | - |
Homo sapiens | CoA + N-acetyl-9-O-acetylneuraminate + CMP | - |
? | |
acetyl-CoA + CMP-N-acetylneuraminate | the N-terminal luminal domain of CASD1 demonstrate sialate 9-O-acetyltransferase activity, transfer of acetyl groups from acetyl-coenzyme A to CMP-activated sialic acid and formation of a covalent acetyl-enzyme intermediate | Homo sapiens | CoA + N-acetyl-9-O-acetylneuraminate + CMP | - |
? | |
acetyl-CoA + GD3 ganglioside | - |
Homo sapiens | CoA + 9'-O-acetyl-GD3 ganglioside | - |
? | |
additional information | enzyme CASD1 mediates 9-O-acetylation of cellular sialoglycans and sialoglycoconjugates | Homo sapiens | ? | - |
? | |
additional information | while the N-terminal luminal domain of CASD1 displays the characteristic fold of an esterase, it does not appear to function as such, no esterase activity with synthetic acetylesterase substrate 4-nitrophenyl acetate nor towards natural O-acetylated sialoglycoconjugates. In vitro SOAT activity of recombinant soluble enzyme sCASD1 | Homo sapiens | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
CASD1 | - |
Homo sapiens |
sialate O-acetyltransferase | - |
Homo sapiens |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
37 | - |
assay at | Homo sapiens |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
6.5 | - |
assay at | Homo sapiens |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
acetyl-CoA | - |
Homo sapiens |
General Information | Comment | Organism |
---|---|---|
evolution | the N-terminal domain of CASD1 differs from the canonical GDSL/SGNH fold by lacking the conserved residues G and N, and is therefore grouped into pfam family PF13839, i.e. GDSL/SGNH-like acylesterase family found in Pmr5 and Cas1p. While the N-terminal luminal domain of CASD1 displays the characteristic fold of an esterase39, it does not appear to function as such, no esterase activity with synthetic acetylesterase substrate 4-nitrophenylacetate nor towards natural O-acetylated sialoglycoconjugates | Homo sapiens |
additional information | homology modelling and topology of human enzyme CASD1 residues 83-290, using the crystal structure of an isoamyl acetate-hydrolysing esterase from Saccharomyces cerevisiae, PDB ID 3mil as template, and predicting a GDSL/SGNH-like alpha/beta-fold that forms the scaffold for a catalytic triad composed of S94, D270 and H273, with S94 as part of a conserved GDS sequence motif, overview. the catalyytic triad is formed by D270, H273, and S94 | Homo sapiens |
physiological function | CASD1 is a sialate O-acetyltransferase that catalyzes the transfer of acetyl groups from acetyl-coenzyme A to CMP-activated sialic acid and formation of a covalent acetyl-enzyme intermediate and serves as key enzyme in the biosynthesis of 9-O-acetylated sialoglycans | Homo sapiens |