L-氮杂环丁烷-2-羧酸对鸡胚肌腱细胞中胶原蛋白糖基化的影响。

Effect of L-azetidine-2-carboxylic acid on glycosylations of collagen in chick-embryo tendon cells.

作者信息

Oikarinen A, Anttinen H, Kivirikko K I

出版信息

Biochem J. 1976 Dec 15;160(3):639-45. doi: 10.1042/bj1600639.

DOI:10.1042/bj1600639

PMID:1016244

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1164281/

Abstract

The glycosylations of hydroxylysine during collagen biosynthesis in isolated chick-embryo tendon cells were studied by using pulse-chase labelling experiments with [14C]-lysine. The hydroxylation of lysine and the glycosylations of hydroxylysine continued after a 5 min pulse label for up to about 10 min during the chase period. These data differ from those obtained previously in isolated chick-embryo cartilage cells, in which, after a similar 5 min pulse label, these reactions continued during the chase period for up to about 20 min. The collagen synthesized by the isolated chick-embryo tendon cells differed markedly from the type I collagen of adult tissues in its degree of hydroxylation of lysine residues and glycosylations of hydroxylysine residues. When the isolated tendon cells were incubated in the presence of L-azetidine-2-carboxylic acid, the degree of glycosylations of hydroxylysine during the first 10 min of the chase period was identical with that in cells incubated without thcarboxylic acid for at least 60 min, whereas no additional glycosylations took place in the control cells after the 10 min time-point. As a consequence, the collagen synthesized in the presence of this compound contained more carbohydrate than did the collagen synthesized by the control cells. Additional experiments indicated that azetidine-2-carboxylic acid did not increase the collagen glycosyltransferase activities in the tendon cells or the rate of glycosylation reactions when added directly to the enzyme incubation mixture. Control experiments with colchicine indicated that the delay in the rate of collagen secretion, which was observed in the presence of azetidine-2-carboxylic acid, did not in itself affect the degree of glycosylations of collagen. The results thus suggest that the increased glycosylations were due to inhibition of the collagen triple-helix formation, which is known to occur in the presence of azetidine-2-carboxylic acid.

摘要

利用[¹⁴C] - 赖氨酸进行脉冲追踪标记实验，研究了分离的鸡胚肌腱细胞中胶原蛋白生物合成过程中羟赖氨酸的糖基化情况。在5分钟脉冲标记后，赖氨酸的羟化和羟赖氨酸的糖基化在追踪期内持续了约10分钟。这些数据与之前在分离的鸡胚软骨细胞中获得的数据不同，在类似的5分钟脉冲标记后，这些反应在追踪期内持续了约20分钟。分离的鸡胚肌腱细胞合成的胶原蛋白在赖氨酸残基的羟化程度和羟赖氨酸残基的糖基化程度上与成年组织的I型胶原蛋白明显不同。当分离的肌腱细胞在L - 氮杂环丁烷 - 2 - 羧酸存在下孵育时，追踪期前10分钟内羟赖氨酸的糖基化程度与在无该羧酸的情况下孵育至少60分钟的细胞相同，而对照细胞在10分钟时间点后没有发生额外的糖基化。因此，在该化合物存在下合成的胶原蛋白比对照细胞合成的胶原蛋白含有更多的碳水化合物。额外的实验表明，氮杂环丁烷 - 2 - 羧酸直接添加到酶孵育混合物中时，不会增加肌腱细胞中胶原蛋白糖基转移酶的活性或糖基化反应的速率。用秋水仙碱进行的对照实验表明，在氮杂环丁烷 - 2 - 羧酸存在下观察到的胶原蛋白分泌速率延迟本身不会影响胶原蛋白的糖基化程度。因此，结果表明糖基化增加是由于胶原蛋白三螺旋形成受到抑制，已知这种抑制在氮杂环丁烷 - 2 - 羧酸存在时会发生。