Studies on beta-crystallin from primate lens.

The major beta-crystallin fractions from the human lens and the lenses of other selected primates have been isolated and partially characterized. Primate beta-crystallins, like those of most other mammals, consist of two heterogenous protein fractions (betaH and beta L) of quite different molecular size. Most of the polypeptide chains comprising the betaH and beta L heteropolymers are common to both fractions. Evidence is presented suggesting that primate betaH-crystallin may be smaller than betaH from other vertebrate species. Additionally, human betaH is found to contain a major component on sodium dodecyl sulfate (SDS) electrophoresis which is much larger (about 60,000 daltons) than other beta-crystallin polypeptides. Immunochemical evidence inidcates that some components of primate beta-crystallin have evolved rapidly, although at least one antigenic component is very conservative and gives a reaction of identity with all other vertebrate beta-crystallins studied.