UniProt functional annotation for Q4WQS0

UniProt code: Q4WQS0.

Organism: Neosartorya fumigata (strain ATCC MYA-4609 / Af293 / CBS 101355 / FGSC A1100) (Aspergillus fumigatus).
Taxonomy: Eukaryota; Fungi; Dikarya; Ascomycota; Pezizomycotina; Eurotiomycetes; Eurotiomycetidae; Eurotiales; Aspergillaceae; Aspergillus.
 
Function: Sialidase is able to release sialic acid from a wide variety of natural substrates including bovine salivary mucin, colominic acid, bovine fetuin, a serum glycoprotein containing both alpha-2-6 and alpha-2-3-linkages in a ratio of about 3:2, and glycoproteins and glycolipids from thermally denatured human lung epithelial cells. Does not show any trans-sialidase activity since it is able to remove terminal sialic acid residues but is unable to catalyze their transfer to the acceptor substrate. 2-keto-3- deoxynononic acid (KDN) is the preferred substrate and A.fumigatus can utilize KDN as a sole carbon source. {ECO:0000269|PubMed:20652740}.
 
Catalytic activity: Hydrolysis of alpha-(2->3)-, alpha-(2->6)-, alpha-(2->8)- glycosidic linkages of terminal sialic acid residues in oligosaccharides, glycoproteins, glycolipids, colominic acid and synthetic substrates. {ECO:0000269|PubMed:20652740, ECO:0000269|PubMed:21247893}.
Biophysicochemical properties: Kinetic parameters: KM=3.3 mM for 4-methylumbelliferyl alpha-D-N-acetylneuraminic acid (MUN) {ECO:0000269|PubMed:20652740, ECO:0000269|PubMed:21247893}; KM=3.1 mM for 4-methylumbelliferyl-alpha-D-N- acetylneuraminylgalactopyranoside {ECO:0000269|PubMed:20652740, ECO:0000269|PubMed:21247893}; KM=0.23 mM for 4-methylumbelliferyl 3-deoxy-D-glycero-alpha-D- galacto-non-2-ulopyranosonic acid (KDN-MU) {ECO:0000269|PubMed:20652740, ECO:0000269|PubMed:21247893}; pH dependence: Optimum pH is 3.5. {ECO:0000269|PubMed:20652740, ECO:0000269|PubMed:21247893};
Induction: Expression is increased during conidial swelling and germination in presence of human serum. {ECO:0000269|PubMed:20652740}.
Similarity: Belongs to the glycosyl hydrolase 33 family. {ECO:0000305}.

Annotations taken from UniProtKB at the EBI.