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

FEBS Letters

Affolter, Hans-Urs²  Hook, Vivian Y.H.¹ 

[1] Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, MD 28014, USA;Institute for Brain Research, University of Zurich, Switzerland

关键词: Prohormone processing enzyme;    Limited proteolysis;    Substance P;    (Human ideal carcinoid);   

DOI  :  10.1016/0014-5793(88)80508-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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 ideal carcinoid which expresses β-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.

【 授权许可】

Unknown