Identification of latent procathepsin H in microsomal lumen: Characterization of proteolytic processing and enzyme activation

Yukio Nishimura, Keitaro Kato

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

Procathepsin H in kidney and liver microsomal lumen was identified to have a molecular mass of 41 kDa by immunoblot analysis. The proenzyme was then concentrated by applying the microsomal contents to a concanavalin A-Sepharose column. When the concanavalin A-adsorbed fraction was incubated at pH 4.0 at 20 °C, the activity measured with synthetic substrate increased 3.5 times over that of the control after 24 h incubation. Immunoblot analysis showed that acidic treatment caused the disappearance of procathepsin H. Thus the proenzyme might be processed to the mature enzyme under acidic conditions. The marked increase of enzymatic activity and the conversion of proenzyme were completely blocked with pepstatin which is a potent inhibitor of aspartic proteases. These results suggested that a protease for processing procathepsin H might be cathepsin D, a major lysosomal aspartic protease. Therefore, procathepsin H seems to be synthesized first in the enzymatically inactive form in endoplasmic reticulum and successively converted into the active form in lysosomes during biosynthesis.

Original languageEnglish
Pages (from-to)712-718
Number of pages7
JournalArchives of Biochemistry and Biophysics
Volume260
Issue number2
DOIs
Publication statusPublished - Feb 1 1988

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology

Fingerprint Dive into the research topics of 'Identification of latent procathepsin H in microsomal lumen: Characterization of proteolytic processing and enzyme activation'. Together they form a unique fingerprint.

Cite this