(a-N-acetylneuraminyl-2,3-b-galactosyl-1,3)-N-acetyl-galactosaminide 6-a-sialyltransferase

Alpha-N-acetylneuraminyl-2,3-beta-galactosyl-1,3-N-acetylgalactosaminide 6-alpha-sialyltransferase (EC 2.4.99.7, sialyltransferase, cytidine monophosphoacetylneuraminate-(alpha-N-acetylneuraminyl-2,3-beta-galactosyl-1,3)-N-acetylgalactosaminide-alpha-2,6-sialyltransferase, alpha-N-acetylneuraminyl-2,3-beta-galactosyl-1,3-N-acetyl-galactosaminide alpha-2,6-sialyltransferase, SIAT7, ST6GALNAC, (alpha-N-acetylneuraminyl-2,3-beta-galactosyl-1,3)-N-acetyl-galactosaminide 6-alpha-sialyltransferase, CMP-N-acetylneuraminate:(alpha-N-acetylneuraminyl-2,3-beta-D-galactosyl-1,3)-N-acetyl-D-galactosaminide alpha-2,6-N-acetylneuraminyl-transferase) is an enzyme with systematic name CMP-N-acetylneuraminate:N-acetyl-alpha-neuraminyl-(2->3)-beta-D-galactosyl-(1->3)- N-acetyl-D-galactosaminide galactosamine-6-alpha-N-acetylneuraminyltransferase.^[1] This enzyme catalyses the following chemical reaction

CMP-N-acetylneuraminate + N-acetyl-alpha-neuraminyl-(2->3)-beta-D-galactosyl-(1->3)-N-acetyl-D-galactosaminyl-R

\rightleftharpoons

CMP + N-acetyl-alpha-neuraminyl-(2->3)-beta-D-galactosyl-(1->3)-[N-acetyl-alpha-neuraminyl-(2->6)]-N-acetyl-D-galactosaminyl-R

This enzyme attaches N-acetylneuraminic acid in alpha-2,6-linkage to N-acetyl-galactosamine only when present in the structure, where R may be protein or p-nitrophenol.

References

↑ Bergh, M.L.E.; Hooghwinkel, G.J.M.; Van den Eijnden, D.H. (1983). "Biosynthesis of the O-glycosidically linked oligosaccharide chains of fetuin. Indications for an α-N-acetylgalactosaminide α2→6 sialyltransferase with a narrow acceptor specificity in fetal calf liver". J. Biol. Chem. 258 (12): 7430–7436. PMID 6190802.

External links

Alpha-N-acetylneuraminyl-2,3-beta-galactosyl-1,3-N-acetylgalactosaminide 6-alpha-sialyltransferase at the US National Library of Medicine Medical Subject Headings (MeSH)

Transferases: glycosyltransferases (EC 2.4)

2.4.1: Hexosyl-
transferases

Glucosyl-	Phosphorylase Starch Glycogen Myo- Glycogen synthase Debranching enzyme Branching enzyme 1,3-Beta-glucan synthase Ceramide glucosyltransferase

Galactosyl-	Lactose synthase B-N-acetylglucosaminyl-glycopeptide b-1,4-galactosyltransferase Glycoprotein-N-acetylgalactosamine 3-beta-galactosyltransferase (C1GALT1)

Glucuronosyl-	B3GAT1 B3GAT2 B3GAT3 UGT1A1 UGT1A3 UGT1A4 UGT1A5 UGT1A6 UGT1A7 UGT1A8 UGT1A9 UGT1A10 UGT2A1 UGT2A2 UGT2A3 UGT2B4 UGT2B7 UGT2B10 UGT2B11 UGT2B15 UGT2B17 UGT2B28 Hyaluronan synthase: HAS1 HAS2 HAS3

Fucosyl-	POFUT1 POFUT2 FUT1 FUT2 FUT3 FUT4 FUT5 FUT6 FUT7 FUT8 FUT9 FUT10 FUT11

Mannosyl-	Dolichyl-phosphate-mannose-protein mannosyltransferase POMT1 POMT2 DPM1 DPM3 ALG1 ALG2 ALG3 ALG6 ALG8 ALG9 ALG12

2.4.2: Pentosyl-
transferases

Ribose

ADP-ribosyltransferase	NAD⁺:diphthamide ADP-ribosyltransferase Diphtheria toxin NAD(P)⁺:arginine ADP-ribosyltransferase Pertussis toxin Cholera toxin Poly ADP ribose polymerase Sirtuin

Phosphoribosyltransferase	Adenine phosphoribosyltransferase Hypoxanthine-guanine phosphoribosyltransferase Uracil phosphoribosyltransferase Amidophosphoribosyltransferase

Other	Purine nucleoside phosphorylase: Thymidine phosphorylase ECGF1

Other

2.4.99: Sialyl
transferases

Enzymes

Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Enzyme kinetics Lineweaver–Burk plot Michaelis–Menten kinetics

Regulation	Allosteric regulation Cooperativity Enzyme inhibitor

Classification	EC number Enzyme superfamily Enzyme family List of enzymes

Types	EC1 Oxidoreductases (list) EC2 Transferases (list) EC3 Hydrolases (list) EC4 Lyases (list) EC5 Isomerases (list) EC6 Ligases (list)

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