人羧肽酶H的酶原形式和成熟形式的鉴定。一种用于肽激素合成的加工酶。

Identification of zymogen and mature forms of human carboxypeptidase H. A processing enzyme for the synthesis of peptide hormones.

作者信息

Hook V Y, Affolter H U

机构信息

Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, MD 28014.

出版信息

FEBS Lett. 1988 Oct 10;238(2):338-42. doi: 10.1016/0014-5793(88)80508-8.

DOI:10.1016/0014-5793(88)80508-8

PMID:2458970

Abstract

Carboxypeptidase H (CPH) is one of several processing enzymes required for the conversion of peptide hormone precursors into their smaller active forms. In this study, high levels of CPH activity was found in a liver metastasis of a human ileal carcinoid which expresses beta-preprotachykinin mRNA and the tachykinin neuropeptides, substance P and substance K. This human CPH showed properties of a zinc-metallopeptidase that is structurally similar to bovine and rat CPH. Immunoblots of the human ileal carcinoma with anti-bovine CPH showed that CPH activity is represented by two proteins of apparent molecular masses 57 and 55 kDa. Cell-free translation of poly(A)+ RNA followed by immunoprecipitation with anti-bovine CPH showed that human CPH mRNA encodes a precursor protein of apparent molecular mass 75 kDa. These data demonstrate that human CPH is synthesized as a zymogen, prepro-CPH, which must be cleaved to form catalytically active CPH.

摘要

羧肽酶H（CPH）是将肽激素前体转化为较小活性形式所需的几种加工酶之一。在本研究中，在表达β-前速激肽原mRNA以及速激肽神经肽P物质和K物质的人回肠类癌肝转移灶中发现了高水平的CPH活性。这种人CPH表现出锌金属肽酶的特性，其结构与牛和大鼠CPH相似。用人回肠癌与抗牛CPH进行免疫印迹分析表明，CPH活性由两种表观分子量分别为57 kDa和55 kDa的蛋白质代表。用抗牛CPH进行免疫沉淀后对聚腺苷酸加尾RNA进行无细胞翻译，结果表明人CPH mRNA编码一种表观分子量为75 kDa的前体蛋白。这些数据表明，人CPH是以酶原形式即前体CPH合成的，必须经过切割才能形成具有催化活性的CPH。