大鼠胰凝乳蛋白酶原在酵母中的表达：对胰凝乳蛋白酶原前肽结构和功能意义的研究

Expression of rat chymotrypsinogen in yeast: a study on the structural and functional significance of the chymotrypsinogen propeptide.

作者信息

Venekei I, Gráf L, Rutter W J

机构信息

Hormone Research Institute, University of California San Francisco 94143-0534, USA.

出版信息

FEBS Lett. 1996 Jan 29;379(2):139-42. doi: 10.1016/0014-5793(95)01483-7.

DOI:10.1016/0014-5793(95)01483-7

PMID:8635579

Abstract

The role of the propeptide sequence and a disulfide bridge between sites 1 and 122 in chymotrypsin has been examined by comparing enzyme activities of wild-type and mutant enzymes. The kinetic constants of mutants devoid of the Cys1-Cys122 disulfide-linked propeptide show that this linkage is not important either for activity or substrate specificity. However this linkage appears to be the major factor in keeping the zymogen stable against non-specific activation. A comparison of zymogen stabilities showed that the trypsinogen propeptide is ten times more effective than the chymotrypsinogen propeptide in preventing non-specific zymogen activation during heterologous expression and secretion from yeast. This feature can also be transferred in trans to chymotrypsinogen; i.e. the chymotrypsin trypsin propeptide chimera forms a stable zymogen.

摘要

通过比较野生型和突变型酶的酶活性，研究了胰凝乳蛋白酶中前肽序列以及1位和122位之间二硫键的作用。缺乏Cys1-Cys122二硫键连接的前肽的突变体的动力学常数表明，这种连接对活性或底物特异性均不重要。然而，这种连接似乎是使酶原对非特异性激活保持稳定的主要因素。酶原稳定性的比较表明，在从酵母中进行异源表达和分泌过程中，胰蛋白酶原前肽在防止非特异性酶原激活方面比胰凝乳蛋白酶原前肽有效十倍。这一特性也可以反式转移到胰凝乳蛋白酶原；即，胰凝乳蛋白酶-胰蛋白酶原前肽嵌合体形成稳定的酶原。