Epithelial mucins and bacterial adhesion - Carbohydrate Chemistry: Chemical and Biological Approaches - page 603

Table 2 Human glycosyltransferase genes involved in O-glycan core biosynthesis and
elongation.

Gene Common name Accession number Ref.

Polypeptide N-Acetyl-galactosaminyltransferases
GALNT1 ppGalNAc-T1 X85018.1 120

GALNT2 ppGalNAc-T2 X85019 120

GALNT3 ppGalNAc-T3 X92689 121

GALNT4 ppGalNAc-T4 Y08564 122

GALNT5 ppGalNAc-T5 AJ245539 123

GALNT6 ppGalNAc-T6 Y08565 124

GALNT7 ppGalNAc-T7 AJ002744 125

GALNT8 ppGalNAc-T8 AJ271385 126

GALNT9 ppGalNAc-T9 AB040672 127

GALNT10 ppGalNAc-T10 AJ505950 128

GALNT11 ppGalNAc-T11 Y12434 129

GALNT12 ppGalNAc-T12 AJ132365 130

GALNT13 ppGalNAc-T13 AJ505991 131

GALNT14 ppGalNAc-T14 Y09324 132

GALNT15 ppGalNAc-T15 NM_054110 133

GALNT16 ppGalNAc-t16 AJ505951 134

GALNT17 ppGalNAc-T17 AJ626725 135

GALNT18 ppGalNAc-T18 AJ626724 135

GALNT19 ppGalNAc-T19 AJ626726 136

GALNT20 ppGalNAc-T20 NM_145292 135

Core Enzymes
C1GALT1 Core 1 b3Gal T1 NM_020156 137

CGNT1 Core 2 b6GlcNAc T1 NM_001490 138

CGNT3 Core 2/4/I b6GlcNAc T2 NM_004751 13

CGNT4 Core 2 b6GlcNAc T3 NM_016591 14

B3GNT6 Core 3 b3GlcNAc T6 NM_138706 17

Galactosyltransferases and N-Acetyl-glucosaminyltransferases (elongation enzymes)
B4GALT1

b4Gal T1 NM_001497 139

B4GALT4 b4Gal T4 NM_003778 140

B4GALT5 b4Gal T5 NM_004776 141

B3GALT5 b3Gal T5 NM_006057 25

B3GNT2 b3GlcNAc T2 AB049584 20

B3GNT3 b3GlcNAc T3 NM_020156 20

B3GNT4 b3GlcNAc T4 NM_020156 20

CGNT2 b6GlcNAc T2 L19659 142

IGnT1 (CGNT3) Core 2/4/I b6GlcNAc T2 NM_004751 13, 143

3.2 Terminal glycosylation of O-glycan chains
3.2.1 Sialylation. Sialyltransferases belong to family 29 of the CAZy
classification and are a subset of glycosyltransferases that use CMP-
Neup5Ac as an activated sugar donor to catalyze the transfer of sialic acid
residues to terminal non-reducing positions of oligosaccharide chains of
glycoproteins and glycolipids. They catalyze the formation of different
linkages (a2-3, a2-6, and a2-8) and differ in their acceptor specificity,
some being dedicated to mucin O-glycan biosynthetic pathways, while
other enzymes show broader substrate specificity (Table 3). 27
Four of the six different a2,3-sialyltransferases that catalyze the
transfer of sialic acid residues in a2,3-linkage onto the terminal Galp
residue are involved in mucin glycan chains biosynthesis (Table 3).