Cathepsin L--a latent proteinase in guinea pig sperm

Biochem Biophys Res Commun. 1988 Mar 15;151(2):827-35. doi: 10.1016/s0006-291x(88)80356-5.

Abstract

Guinea pig spermatozoa were found to contain a fully-latent cysteine proteinase that could be unmasked by incubating epididymal sperm for 2 hr at pH 3.5 and 37 degrees C. The proteinase was identified as cathepsin L (EC 3.4.22.15) on the basis of its optimal hydrolysis of benzyloxycarbonyl-Phe-Arg-7-(4-methyl)coumarylamide (Z-Phe-Arg-NMec) at pH 5.5; lack of action on Z-Arg-Arg-NMec and Arg-NMec; urea-enhanced digestion of azocasein; marked sensitivity to thiol reagents, leupeptin, Z-Phe-Phe-CHN2, and L-trans-epoxy-succinylleucylamido(3-methyl)butane (Ep-475 or E-64-c); and insensitivity to pepstatin and serine proteinase inhibitors. Gossypol, a male antifertility agent, was inhibitory. The unmasking phenomenon was reversibly inhibited by HgCl2 and mersalyl acid, and prevented by leupeptin and Ep-475, but not by pepstatin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cathepsin L
  • Cathepsins / isolation & purification
  • Cathepsins / metabolism*
  • Cysteine Endopeptidases
  • Dithiothreitol / pharmacology
  • Endopeptidases*
  • Guinea Pigs
  • Hydrogen-Ion Concentration
  • Kinetics
  • Leucine / analogs & derivatives
  • Leucine / pharmacology
  • Leupeptins / pharmacology
  • Male
  • Mercuric Chloride / pharmacology
  • Protease Inhibitors / pharmacology
  • Spermatozoa / enzymology*

Substances

  • Leupeptins
  • Protease Inhibitors
  • Mercuric Chloride
  • N-(N-(3-carboxyoxirane-2-carbonyl)leucyl)isoamylamine
  • Cathepsins
  • Endopeptidases
  • Cysteine Endopeptidases
  • Cathepsin L
  • Leucine
  • Dithiothreitol