The degradation of alpha-crystallin at its carboxyl-terminal portion by calpain in bovine lens

Invest Ophthalmol Vis Sci. 1986 Aug;27(8):1269-73.


Bovine lens calpain (Ca2+-dependent cysteine proteinase; EC was shown to catalyze limited proteolysis of A and B chains of alpha-crystallin in vitro. The sites of cleavages were determined by isolating and analyzing the peptide fragments formed using several different methods, including high-performance liquid chromatography, cyanogen bromide cleavage, and carboxypeptidase digestion. The results indicated that calpain cleaved both A and B chains at their respective carboxyl-terminal regions. A chain was cleaved at A(Arg163-Glu164) bond and A(Ser162-Arg163) bond, the former being split with 2.4 times preference over the latter. B chain was cleaved at B(Thr170-Ala171) bond and B (Arg163-Glu164) bond, the former being preferred 6.5 times. Peptide cleavage at any other sites were not detected by the present method of analysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / analysis
  • Animals
  • Calpain / metabolism
  • Calpain / pharmacology*
  • Calpain / physiology
  • Carboxypeptidases / metabolism
  • Cattle
  • Chromatography, High Pressure Liquid
  • Crystallins / metabolism*
  • Hydrolysis
  • Lens, Crystalline / analysis
  • Lens, Crystalline / metabolism
  • Peptide Fragments / analysis


  • Amino Acids
  • Crystallins
  • Peptide Fragments
  • Carboxypeptidases
  • Calpain