Protamine: a unique and potent inhibitor of oligopeptidase B

✍ Scribed by Akihiko Tsuji; Tadashi Yoshimoto; Keizo Yuasa; Yoshiko Matsuda

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 154 KB
• Volume: 12
• Category: Article
• ISSN: 1075-2617
• DOI: 10.1002/psc.683

✦ Synopsis

Abstract

Oligopeptidase B is a serine endopeptidase found in prokaryotes, unicellular eukaryotes and higher plants. The enzyme has been shown recently to play a central role in the pathogenesis of several parasitic diseases such as African trypanosomiasis, and to be a potential therapeutic target. This study reports that protamine, a basic peptide rich in arginine, is a potent inhibitor at the nanomolar level of oligopeptidase B from E. coli and wheat. Protamines 1B, 2C, 3A and TP17 displayed similar inhibitory activities and were capable of binding strongly to oligopeptidase B without proteolytic cleavage. The concentration of protamine needed for 50% inhibition (IC~50~) of oligopeptidase B was 10^4^‐fold lower than the IC~50~ of trypsin. Oligopeptidase B was highly sensitive to inhibition by protamines even in the presence of serum (IC~50~, 1 µM). These data indicate that protamines might provide information useful for the design of more specific synthetic oligopeptidase B inhibitors. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd.