On the components of rabbit lens -crystallin

Abstract

This paper reports attempts to obtain a homogeneous component of rabbit eye lens ▪-crystallin and the partial characterization of five fractions from ▪-crystallin. 1. 1) The fractionation of ▪-crystallin into eight components using CM-cellulose chromatography and a combined ionic strength-pH gradient is described. 2. 2) Five components were examined for their C-terminal amino acids before and after succinylation. Their polyacrylamide gel electrophoresis patterns and amino acid compositions were determined. Tryptic-peptide maps of the reduced, aminoethylated and cyanogen bromide-cleaved components were prepared. 3. 3) Despite considerable fractionation, it did not appear that any of the components examined were homogeneous. However, there were striking similarities in amino acid composition, tryptic-peptide maps, and C-terminal amino acids. Our results are in general agreement with those of Björk (5) for bovine ▪-crystallin. 4. 4) We suggest the several components of ▪-crystallin arise from minor, non-lethal evolutionary alterations in primary structure.