β4-N-Acetylgalactosaminyltransferase (β4GalNAcT) is a key enzyme to catalyze the conversion of GM3, GD3, and lactosylceramide (LacCer) to GM2, GD2, and asialo- GM2 (GA2), respectively (Yamashiro et al. 1995). This step is critical for the synthesis of all complex gangliosides such as GM1, GD1a, GD1b, GT1b, and GQ1b which are enriched in the nervous system of vertebrates. Therefore, all complex gangliosides are synthesized via the direct products of this enzyme. The cDNAs of β4GalNAcT were isolated by a eularyocyte expression cloning system for the first time as a glycosyl- transferase gene responsible for the ganglioside synthesis in 1992 (Nagata et al. 1992). This enzyme utilizes only glycolipid acceptors, not glycoproteins, and no other enzymes (genes) catalyzing similar functions have been detected to date.
KeywordsAscites Hepatoma Complex Ganglioside Ganglioside Expression Alternative Exon Usage Ganglioside Synthesis
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