来自胚胎鸡肌肉的唾液酸转移酶对乳糖-N-新六糖神经酰胺的唾液酸化作用。
Sialylation of lacto-N-neohexaosylceramide by sialyltransferase from embryonic chicken muscle.
作者信息
Dasgupta S, Chien J L, Hogan E L
出版信息
Biochim Biophys Acta. 1986 Apr 15;876(2):363-70. doi: 10.1016/0005-2760(86)90296-1.
A sialyltransferase which catalyzes the in vitro biosynthesis of N-acetylneuraminosyllacto-N-neohexaosylceramide from lacto-N-neohexaosylceramide and CMP-NeuAc has been examined in embryonic chicken breast muscle. The maximum enzyme activity was observed in 11-12-day-old embryos. The enzyme has optimum activity at pH 6.8 in the presence of Triton CF-54 and Mg2+. The apparent Km values for lacto-N-neohexaosylceramide and CMP-NeuAc were 0.9 and 0.67 mM, respectively. The enzymic product was characterized by TLC, neuraminidase hydrolysis and permethylation analysis. The structure was identical to authentic N-acetylneuraminosyllacto-N-neohexaosylceramide from chicken muscle. In addition, a disialo derivative has been detected that constitutes 15% of the total radioactivity incorporated. The two sialic acids connected by sialosyl-sialosyl linkage were attached to the terminal galactose residue. To our knowledge, this is the first report of biosynthesis of this disialo compound.
一种催化从乳糖-N-新己糖神经酰胺和CMP-唾液酸在体外生物合成N-乙酰神经氨酸乳糖-N-新己糖神经酰胺的唾液酸转移酶已在鸡胚胸肌中进行了研究。在11至12日龄的胚胎中观察到最大酶活性。该酶在Triton CF-54和Mg2+存在下，pH 6.8时具有最佳活性。乳糖-N-新己糖神经酰胺和CMP-唾液酸的表观Km值分别为0.9和0.67 mM。酶产物通过TLC、神经氨酸酶水解和全甲基化分析进行表征。其结构与来自鸡肌肉的 authentic N-乙酰神经氨酸乳糖-N-新己糖神经酰胺相同。此外，还检测到一种二唾液酸衍生物，其占掺入总放射性的15%。通过唾液酸-唾液酸连接相连的两个唾液酸连接到末端半乳糖残基上。据我们所知，这是关于这种二唾液酸化合物生物合成的首次报道。
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