CHARACTERIZATION OF CYANOGEN BROMIDE PEPTIDES FROM ALPHA2 CHAIN OF CHICK SKIN COLLAGEN

Cleavage of the αl chain of chick skin collagen with cyanogen bromide gives rise to six peptides which have been separated and purified by a combination of ion-exchange and molecular sieve chromatography. The finding of six peptides is consistent with the known content of methionine in the αl chain (five) of chick skin collagen. The molecular weights of these peptides range from 31,000 to 317 and total 91,000, a value which is in reasonable agreement with the known molecular weight of 95,000 for the α chain. The amino acid composition of each peptide is clearly unique and the six peptides account for all of the known amino acid content of the original al chain within experimental error. The six cyanogen bromide peptides from the α2 chain of chick skin collagen are clearly homologous to the corresponding peptides derived from the α2 chain of rat skin collagen and identical in every examined respect with the cyanogen bromide peptides from the α2 chain of chick bone collagen. Since it was previously shown that cyanogen bromide cleavage of the al chains from chick bone and skin collagens yielded identical peptides with regard to amino acid composition and molecular weight, the differences in the properties of bone and skin collagens are unlikely to be explained on the basis of differences in the primary structure. © 1969, American Chemical Society. All rights reserved.