Yanagisawa K
Hokkaido Igaku Zasshi. 1985 Sep;60(5):662-70.
A UDP-N-acetylgalactosamine: ganglioside GM3 beta-N-acetylgalactosaminyltransferase which catalyzes the conversion of ganglioside GM3 to GM2 has been purified over 6,000-fold from a Triton X-100 extract of rat liver microsomes by affinity chromatography on UDP-hexanolamine-Sepharose and GM3-acid Sepharose. The purified enzyme is composed of two non-identical subunits with apparent molecular weights of 70,000 and 64,000 on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme has a pH optimum of pH 6.7-6.9 and requires divalent cations such as Ni2+ or Mn2+. Studies on substrate specificity indicates that GM3 containing N-acetylneuraminic acid and GM3 containing N-glycolylneuraminic acid were both good acceptors. The oligosaccharide of GM3, sialyllactose was also a good acceptor, which indicates that the preferred acceptor substrate has the general structure NeuAc alpha 2- or NeuGc alpha 2-3Gal beta 1-4Glc-O-R, in which the nature of the R moiety has relatively little effect on activity.
一种催化神经节苷脂GM3转化为GM2的UDP-N-乙酰半乳糖胺：神经节苷脂GM3β-N-乙酰半乳糖胺基转移酶，已通过UDP-己醇胺-琼脂糖和GM3-酸性琼脂糖亲和层析，从大鼠肝脏微粒体的Triton X-100提取物中纯化了6000多倍。在十二烷基硫酸钠聚丙烯酰胺凝胶电泳上，纯化后的酶由两个不同的亚基组成，表观分子量分别为70,000和64,000。该酶的最适pH为6.7 - 6.9，需要二价阳离子如Ni2+或Mn2+。底物特异性研究表明，含有N-乙酰神经氨酸的GM3和含有N-羟乙酰神经氨酸的GM3都是良好的受体。GM3的寡糖唾液乳糖也是一种良好的受体，这表明优选的受体底物具有一般结构NeuAcα2-或NeuGcα2-3Galβ1-4Glc-O-R，其中R部分的性质对活性影响相对较小。
