The influence of isolation conditions on the molecular weight of bovine alpha-crystallin

The molecular weight of bovine alpha-crystallin, isolated at 37 degrees C, was studied and found to be about 800,000. This contrasts with the results of Thomson and Augusteyn (Thomson, J. A., and Augusteyn, R. C. (1983) Exp. Eye Res. 37, 367-377) who isolated a species of about half this molecular weight. We show here that this form of alpha-crystallin can only be isolated under unphysiological conditions with regard to buffer pH and ionic strength.