Sialyltransferases and Other Enzymes Involved in the Biosynthesis of Gangliosides

Abstract

The sialyltransferases involved in the biosynthesis of gangliosides were summarized in Table 1. The simplest sialosylglycolipid is GM3 except for GM4 (sialylgalactosyl ceramide). GM3 is located at the starting point of all ganglio-series glycolipids, extending to a-series, b-series and c-series gangliosides. GM3 synthase is called ST3Gal-V (Tsuji et al. 1996; Furukawa et al. 2007). GD3 synthase is the key enzyme for the synthesis of b-series and c-series gangliosides (GT3 synthase, Nakayama et al. 1996). GD3 synthase is called ST8Sia-I (Tsuji et al. 1996; Furukawa et al. 2007). After extending ganglio-core chain by GM2/GD2/GA2 synthase (Furukawa et al. 2007) and GM1/GD1b/GA1 synthase (Furukawa et al. 2007), GD1a/GT1b/GM1b synthase adds NeuAc to Gal at the nonreducing end (Tsuji et al. 1996). Then GT1a/GQ1b/GD1c synthase catalyzes biosynthesis of GT1a, GQ1b, or GD1c from GD1a, GT1b, or GM1b, respectively (Tsuji et al. 1996).