Myllylä R
Eur J Biochem. 1976 Nov 1;70(1):225-31. doi: 10.1111/j.1432-1033.1976.tb10973.x.
The mechanism of collagen glucosyltransferase reaction was studied with enzyme preparations purified about 2500-5000-fold from extract of homogenate of whole chick embryos. Data obtained in experiments on initial velocity and inhibition kinetics of the reaction were consistent with an ordered mechanism in which the substrates are bound to the enzyme in the following order: Mn2+, UDP-glucose and collagen substrate, the addition of Mn2+ being at thermodynamic equilibrium and the binding site of the UDP-glucose to the enzyme not being the same as that for Mn2+ and collagen substrate. Only one metal co-factor seems to be involved in the reaction. The collagen substrate can probably also react in some conditions with enzyme-Mn2+ and with enzyme-Mn2+-UDP, and the UDP with the free enzyme, but in all these instances dead-end complexes are formed. Evidence is presented for an ordered release of the products in the following order: glucosylated collagen, UDP and Mn2+, in which Mn2+ need not leave the enzyme during each catalytic cycle.
利用从全鸡胚匀浆提取物中纯化约2500 - 5000倍的酶制剂，研究了胶原蛋白葡萄糖基转移酶反应的机制。关于该反应初速度和抑制动力学的实验数据与一种有序机制一致，即底物按以下顺序与酶结合：Mn2 +、UDP - 葡萄糖和胶原蛋白底物，Mn2 +的添加处于热力学平衡状态，UDP - 葡萄糖与酶的结合位点与Mn2 +和胶原蛋白底物的不同。该反应似乎只涉及一种金属辅助因子。胶原蛋白底物在某些条件下可能也会与酶 - Mn2 +以及酶 - Mn2 + - UDP反应，UDP会与游离酶反应，但在所有这些情况下都会形成终止复合物。有证据表明产物按以下顺序有序释放：糖基化胶原蛋白、UDP和Mn2 +，其中Mn2 +在每个催化循环中不一定离开酶。
