INVESTIGATIONS ON POLYPEPTIDE CHAINS OF ALPHA-CRYSTALLIN

A procedure is described for the purification of α-crystallin including isoelectric precipitation with ethanol and gel filtration on Sephadex G-200. The C-terminal amino acid of α-crystallin was found to be serine only. The mean molecular weight of the subunits of α-crystallin, calculated from C-terminal analyses is 26.000. This value is consistent with the amount of serine found after hydrazinolysis. From analyses of the fragments produced after cyanogen bromide cleavage it can be concluded that at least two different types of subunits are present in the α-crystallin aggregate. The new N-terminal groups after cyanogen-bromide cleavage were identified as aspartic acid and leucine residues. © 1968 Academic Press Inc. (London) Limited.