(N-acetylneuraminyl)-galactosylglucosylceramide N-acetylgalactosaminyltransferase explained

(N-acetylneuraminyl)-galactosylglucosylceramide N-acetylgalactosaminyltransferase
Ec Number:	2.4.1.92
Cas Number:	67338-98-1

(N-acetylneuraminyl)-galactosylglucosylceramide N-acetylgalactosaminyltransferase (uridine diphosphoacetylgalactosamine-ganglioside GM3 acetylgalactosaminyltransferase, ganglioside GM2 synthase, ganglioside GM3 acetylgalactosaminyltransferase, GM2 synthase, UDP acetylgalactosamine-(N-acetylneuraminyl)-D-galactosyl-D-glucosylceramide acetylgalactosaminyltransferase, UDP-N-acetyl-D-galactosamine:1-O-[O-(N-acetyl-alpha-neuraminyl)-(2->3)-O-beta-D-galactopyranosyl-(1->4)-beta-D-glucopyranosyl]-ceramide 1,4-beta-N-acetyl-D-galactosaminyltransferase acetylgalactosaminyltransferase, UDP-N-acetylgalactosamine GM3 N-acetylgalactosaminyltransferase, uridine diphosphoacetylgalactosamine-acetylneuraminylgalactosylglucosylceramide acetylgalactosaminyltransferase, uridine diphosphoacetylgalactosamine-hematoside acetylgalactosaminyltransferase, GM2/GD2-synthase, beta-1,4N-aetylgalactosaminyltransferase, asialo-GM2 synthase, GalNAc-T, UDP-N-acetyl-D-galactosamine:(N-acetylneuraminyl)-D-galactosyl-D-glucosylceramide N-acetyl-D-galactosaminyltransferase) is an enzyme with systematic name UDP-N-acetyl-D-galactosamine:1-O-(O-(N-acetyl-alpha-neuraminyl)-(2->3)-O-beta-D-galactopyranosyl-(1->4)-beta-D-glucopyranosyl)-ceramide 4-beta-N-acetyl-D-galactosaminyltransferase.^{[1] [2] [3] [4] [5] [6] [7]} This enzyme catalyses the following chemical reaction:

UDP-N-acetyl-D-galactosamine + 1-O-[O-(N-acetyl-alpha-neuraminyl)-(2->3)-O-beta-D-galactopyranosyl-(1->4)-beta-D-glucopyranosyl]-ceramide

\rightleftharpoons UDP + 1-O-[O-2-(acetylamino)-2-deoxy-beta-D-galactopyranosyl-(1->4)-O-[N-acetyl-alpha-neuraminyl-(2->3)]-O-beta-D-galactopyranosyl-(1->4)-beta-D-glucopyranosyl]-ceramide

This enzyme catalyses the formation of the gangliosides (i.e. sialic-acid-containing glycosphingolipids) GM2, GD2 and SM2 from GM3, GD3 and SM3, respectively.

Notes and References

1. Dicesare JL, Dain JA . The enzymic synthesis of ganglioside. IV. UDP-N-acetylgalactosamine: (N-acetylneuraminyl)-galactosylglucosyl ceramide N-acetylgalactosaminyltransferase in rat brain . Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism . 231 . 2 . 385–93 . March 1971 . 5554906 . 10.1016/0005-2760(71)90151-2 .
2. Pohlentz G, Klein D, Schwarzmann G, Schmitz D, Sandhoff K . Both GA2, GM2, and GD2 synthases and GM1b, GD1a, and GT1b synthases are single enzymes in Golgi vesicles from rat liver . Proceedings of the National Academy of Sciences of the United States of America . 85 . 19 . 7044–8 . October 1988 . 3140234 . 282120 . 10.1073/pnas.85.19.7044 . 1988PNAS...85.7044P . free .
3. Hidari JK, Ichikawa S, Furukawa K, Yamasaki M, Hirabayashi Y . beta 1-4N-acetylgalactosaminyltransferase can synthesize both asialoglycosphingolipid GM2 and glycosphingolipid GM2 in vitro and in vivo: isolation and characterization of a beta 1-4N-acetylgalactosaminyltransferase cDNA clone from rat ascites hepatoma cell line AH7974F . The Biochemical Journal . 303 (Pt 3) . 957–65 . November 1994 . 3 . 7980468 . 1137639 . 10.1042/bj3030957 .
4. Hashimoto Y, Sekine M, Iwasaki K, Suzuki A . Purification and characterization of UDP-N-acetylgalactosamine GM3/GD3 N-acetylgalactosaminyltransferase from mouse liver . The Journal of Biological Chemistry . 268 . 34 . 25857–64 . December 1993 . 10.1016/S0021-9258(19)74467-6 . 8245020 . free .
5. Nagai K, Ishizuka I . Biosynthesis of monosulfogangliotriaosylceramide and GM2 by N-acetylgalactosaminyltransferase from rat brain . Journal of Biochemistry . 101 . 5 . 1115–27 . May 1987 . 3115968 . 10.1093/oxfordjournals.jbchem.a121976 .
6. Furukawa K, Takamiya K, Furukawa K . Beta1,4-N-acetylgalactosaminyltransferase--GM2/GD2 synthase: a key enzyme to control the synthesis of brain-enriched complex gangliosides . Biochimica et Biophysica Acta (BBA) - General Subjects . 1573 . 3 . 356–62 . December 2002 . 12417418 . 10.1016/s0304-4165(02)00403-8 .
7. Yamashita T, Wu YP, Sandhoff R, Werth N, Mizukami H, Ellis JM, Dupree JL, Geyer R, Sandhoff K, Proia RL . Interruption of ganglioside synthesis produces central nervous system degeneration and altered axon-glial interactions . Proceedings of the National Academy of Sciences of the United States of America . 102 . 8 . 2725–30 . February 2005 . 15710896 . 549464 . 10.1073/pnas.0407785102 . 2005PNAS..102.2725Y . free .