Reaction: UDP-N-acetyl-α-D-galactosamine + 3-O-[N-acetyl-β-D-glucosaminyl-(1→4)-α-D-mannosyl]-L-threonyl-[protein] = UDP + 3-O-[N-acetyl-β-D-galactosaminyl-(1→3)-N-acetyl-β-D-glucosaminyl-(1→4)-α-D-mannosyl]-L-threonyl-[protein]
For diagram of reaction click here.
Other name(s): B3GALNT2
Systematic name: UDP-N-acetyl-α-D-galactosamine:N-acetyl-β-D-glucosaminyl-(1→4)-α-D-mannosyl-threonyl-[protein] 3-β-N-acetyl-D-galactosaminyltransferase
Comments: The human protein is specific for UDP-N-acetyl-α-D-galactosamine as donor [1]. The enzyme is involved in the formation of a phosphorylated trisaccharide on a threonine residue of α-dystroglycan, an extracellular peripheral glycoprotein that acts as a receptor for extracellular matrix proteins containing laminin-G domains.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Hiruma, T., Togayachi, A., Okamura, K., Sato, T., Kikuchi, N., Kwon, Y.D., Nakamura, A., Fujimura, K., Gotoh, M., Tachibana, K., Ishizuka, Y., Noce, T., Nakanishi, H. and Narimatsu, H. A novel human β1,3-N-acetylgalactosaminyltransferase that synthesizes a unique carbohydrate structure, GalNAcβ1-3GlcNAc. J. Biol. Chem. 279 (2004) 14087-14095. [PMID: 14724282]
2. Yoshida-Moriguchi, T., Willer, T., Anderson, M.E., Venzke, D., Whyte, T., Muntoni, F., Lee, H., Nelson, S.F., Yu, L. and Campbell, K.P. SGK196 is a glycosylation-specific O-mannose kinase required for dystroglycan function. Science 341 (2013) 896-899. [PMID: 23929950]