Reaction: UDP-N-acetyl-α-D-galactosamine + O-(N-acetyl-α-neuraminyl)-(2→3)-O-β-D-galactopyranosyl-(1→4)-β-D-glucopyranosyl-(1↔1)-ceramide = UDP + O-2-(acetylamino)-2-deoxy-β-D-galactopyranosyl-(1→4)-O-[N-acetyl-α-neuraminyl-(2→3)]-O-β-D-galactopyranosyl-(1→4)-β-D-glucopyranosyl-(1↔1)-ceramide
For diagram of reaction click here.
Glossary: ganglioside GM2 = 1-O-[O-2-(acetylamino)-2-deoxy-β-D-galactopyranosyl-(1→4)-O-[N-acetyl-α-neuraminosyl-(2→3)]-O-β-D-galactopyranosyl-(1→4)-β-D-glucopyranosyl]-ceramide
ganglioside GM3 = 1-O-[O-(N-acetyl-α-neuraminosyl)-(2→3)-O-β-D-galactopyranosyl-(1→4)-β-D-glucopyranosyl]-ceramide
ganglioside GD3 = 1-O-[O-(N-acetyl-α-neuraminosyl)-(2→8)-O-(N-acetyl-α-neuraminosyl)-(2→3)-O-β-D-galactopyranosyl-(1→4)-β-D-glucopyranosyl]-ceramide
ganglioside GD2 = 1-O-[O-(N-acetyl-α-neuraminosyl)-(2→8)-O-(N-acetyl-α-neuraminosyl)-(2→3)-O-[2-(acetylamino)-2-deoxy-β-D-galactopyranosyl-(1→4)]-O-β-D-galactopyranosyl-(1→4)-β-D-glucopyranosyl]-ceramide
ganglioside SM3 = 1-O-[4-O-(3-O-sulfo-β-D-galactopyranosyl)-β-D-glucopyranosyl]-ceramide
ganglioside SM2 = 1-O-[O-2-(acetylamino)-2-deoxy-β-D-galactopyranosyl-(1→4)-O-3-O-sulfo-β-D-galactopyranosyl-(1→4)-β-D-glucopyranosyl]-ceramide
Other name(s): uridine diphosphoacetylgalactosamine-ganglioside GM3 acetylgalactosaminyltransferase; ganglioside GM2 synthase; ganglioside GM3 acetylgalactosaminyltransferase; GM2 synthase; UDP acetylgalactosamine-(N-acetylneuraminyl)-D-galactosyl-D-glucosylceramide acetylgalactosaminyltransferase; UDP-N-acetylgalactosamine GM3 N-acetylgalactosaminyltransferase; uridine diphosphoacetylgalactosamine-acetylneuraminylgalactosylglucosylceramide acetylgalactosaminyltransferase; uridine diphosphoacetylgalactosamine-hematoside acetylgalactosaminyltransferase; GM2/GD2-synthase; β-1,4N-aetylgalactosaminyltransferase; asialo-GM2 synthase; GalNAc-T; UDP-N-acetyl-D-galactosamine:(N-acetylneuraminyl)-D-galactosyl-D-glucosylceramide N-acetyl-D-galactosaminyltransferase; UDP-N-acetyl-D-galactosamine:1-O-[O-(N-acetyl-α-neuraminosyl)-(2→3)-O-β-D-galactopyranosyl-(1→4)-β-D-glucopyranosyl]-ceramide (1→4)-β-N-acetyl-D-galactosaminyltransferase
Systematic name: UDP-N-acetyl-α-D-galactosamine:O-(N-acetyl-α-neuraminyl)-(2→3)-O-β-D-galactopyranosyl-(1→4)-β-D-glucopyranosyl-(1↔1)-ceramide 4-β-N-acetyl-D-galactosaminyltransferase
Comments: This enzyme catalyses the formation of the gangliosides (i.e. sialic-acid-containing glycosphingolipids) GM2, GD2 and SM2 from GM3, GD3 and SM3, respectively. Asialo-GM3 [3] and lactosylceramide [2] are also substrates, but glycoproteins and oligosaccharides are not substrates.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 67338-98-1
References:
1. Dicesare, J.L. and Dain, J.A. The enzymic synthesis of ganglioside. IV. UDP-N-acetylgalactosamine: (N-acetylneuraminyl)-galactosylglucosyl ceramide N-acetylgalactosaminyltransferase in rat brain. Biochim. Biophys. Acta 231 (1971) 385-393. [PMID: 5554906]
2. Pohlentz, G., Klein, D., Schwarzmann, G., Schmitz, D. and Sandhoff, K. Both GA2, GM2, and GD2 synthases and GM1b, GD1a, and GT1b synthases are single enzymes in Golgi vesicles from rat liver. Proc. Natl. Acad. Sci. USA 85 (1988) 7044-7048. [PMID: 3140234]
3. Kazuya, I.-P., Hidari, J.K., Ichikawa, S., Furukawa, K., Yamasaki, M. and Hirabayashi, Y. β1-4N-Acetylgalactosaminyltransferase can synthesize both asialoglycosphingolipid GM2 and glycosphingolipid GM2 in vitro and in vivo: isolation and characterization of a β1-4N-acetylgalactosaminyltransferase cDNA clone from rat ascites hepatoma cell line AH7974F. Biochem. J. 303 (1994) 957-965. [PMID: 7980468]
4. Hashimoto, Y., Sekine, M., Iwasaki, K. and Suzuki, A. Purification and characterization of UDP-N-acetylgalactosamine GM3/GD3 N-acetylgalactosaminyltransferase from mouse liver. J. Biol. Chem. 268 (1993) 25857-25864. [PMID: 8245020]
5. Nagai, K. and Ishizuka, I. Biosynthesis of monosulfogangliotriaosylceramide and GM2 by N-acetylgalactosaminyltransferase from rat brain. J. Biochem. (Tokyo) 101 (1987) 1115-1127. [PMID: 3115968]
6. Furukawa, K., Takamiya, K. and Furukawa, K. β1,4-N-Acetylgalactosaminyltransferase—GM2/GD2 synthase: a key enzyme to control the synthesis of brain-enriched complex gangliosides. Biochim. Biophys. Acta 1573 (2002) 356-362. [PMID: 12417418]
7. Yamashita, T., Wu, Y.P., Sandhoff, R., Werth, N., Mizukami, H., Ellis, J.M., Dupree, J.L., Geyer, R., Sandhoff, K. and Proia, R.L. Interruption of ganglioside synthesis produces central nervous system degeneration and altered axon-glial interactions. Proc. Natl. Acad. Sci. USA 102 (2005) 2725-2730. [PMID: 15710896]