A fractionation of insoluble rat skin collagen

After extraction of 1% of the total collagen of rat skin by 150 mM NaCl, a 1% SDS solution extracts 80% of the total collagen, while the residue is extracted by a mixture of beta mercapto-ethanol and SDS. These extractions, which respect the peptide linkages, cleave the allysyl cross-links. They provide an insight on the composition of some insoluble collagen molecules of the skin and on the importance of disulfide bridges in their architecture.