INTERMOLECULAR CROSS-LINKING OF COLLAGEN AND THE IDENTIFICATION OF A NEW BETA-COMPONENT.

Extraction of skin with 5M guanidine after salt and acid extraction yields a gelatin fraction which contains a greater proportion of double-chain (beta) components than can be accounted for by intramolecular cross-linking of collagen molecules. This fraction also contains a new beta-component, identified as the dimer of alpha2 and designated beta(22). This dimer must be formed by intermolecular crosslinking since each collagen molecule contains only one alpha2 chain. Thus, direct evidence is presented for the occurrence of both inter- and intramolecular crosslinking by what appears to be a single continuous process.