Endothelin 1 hydrolysis by rat kidney membranes

FEBS Letters

Yamaguchi, Toru¹  Fukase, Masaaki¹  Chihara, Kazuo¹  Arao, Makoto¹  Sugimoto, Toshitsugu¹ 

[1] Third Division, Department of Medicine, Kobe University School of Medicine, Kobe, Japan

关键词: Endothelin 1: Kidney membrane;    Metallo-endopeptidase;    Endopeptidase 24;    11;    Peptide hydrolysis;    Rat kidney;   

DOI  :  10.1016/0014-5793(92)80794-H

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Hydrolysis of endothelin 1 by rat kidney membranes was investigated using a reverse-phase HPLC and an automated gas-phase protein sequencer. Endothelin 1 was hydrolyzed into four major fragments which were detected by HPLC, Phosphoramidon, an inhibitor of neutral endopeptidase 24,11, almost completely suppressed the production of three fragments, but one fragment was not affected by the inhibitor. Analysis of N-terminal sequences of the degradation products revealed that the phosphoramidon-sensitive fragments were generated by cleavage at the Ser⁵–Leu⁶ bond of endothelin 1 that was identical with its cleavage site by purified rat endopeptidase 24,11, reported previously. The phosphoramidon-insensitive fragment was produced by cleavage at Leu¹⁷–Asp¹⁸, which was distinct from the sites by endopeptidase 24,11, but corresponded to that by a phosphoramidon-insensitive metallo-endopeptidase recently isolated from rat kidney membranes by μs [(1992) Eur. J. Biochem. 204, 547–552]. Kinetic determination of endothelin 1 hydrolysis by the isolated enzyme yielded values of K_m =71.5 μM and k _cal=1.49 s⁻¹, giving a ratio of k_{cal K m} =2.08 × 10⁴ s⁻¹·M⁻¹. The K_m value was much higher and the k _cal/K _m value was much lower than those for rat endopeptidase 24,11 reported previously. Thus, endopeptidase 24,11 appears to hydrolyze endothelin 1 more efficiently than the isolated enzyme does. Both enzymes may play physiological roles in the metabolism of endothelin 1 by rat kidney membranes in vivo.

【 授权许可】

Unknown