牛血清唾液酸转移酶：与年龄和激素相关的变化。

Sialyltransferase of bovine serum: age- and hormone-related changes.

作者信息

Sherblom A P, Smagula R M, Moody C E, Anderson G W

出版信息

Comp Biochem Physiol B. 1986;84(3):309-13. doi: 10.1016/0305-0491(86)90082-9.

Abstract

Sialyltransferase activity of bovine serum with the acceptor asialofetuin exhibits a pH optimum at 6.0-6.5, no divalent cation dependence, and a Km for CMP-sialic acid of 0.05 mM. Although a 2-fold increase in sialyltransferase activity with the acceptor asialofetuin is observed in serum samples from 2-day-old vs 20-day-old calves, the relative activity towards other glycoprotein acceptors is not different between the groups. With the acceptor lactose, the major product (greater than 95%) for all samples is 3'-sialyllactose, suggesting that the elevated levels of sialyltransferase in 2-day-old calves are due to Gal-R (alpha 2-3) sialyltransferase.

摘要

以去唾液酸胎球蛋白作为受体时，牛血清的唾液酸转移酶活性在pH 6.0 - 6.5时表现出最佳值，不依赖二价阳离子，对CMP - 唾液酸的Km值为0.05 mM。尽管在2日龄犊牛与20日龄犊牛的血清样本中，以去唾液酸胎球蛋白作为受体时唾液酸转移酶活性增加了2倍，但两组对其他糖蛋白受体的相对活性并无差异。以乳糖作为受体时，所有样本的主要产物（超过95%）是3'-唾液酸乳糖，这表明2日龄犊牛中唾液酸转移酶水平升高是由于Gal - R（α2 - 3）唾液酸转移酶所致。