Abstract

Soluble rat tail tendon collagen has been tanned by reaction with 33% basic chromium sulphate. The reaction product was then treated with cyanogen bromide and pepsin to release peptides containing bound Cr(III), which were separated and partially purified by column chromatography. The amino acid sequences around the Cr(III)-binding sites of two of the purified peptides were determined. Glutamic and aspartic acids have each been directly shown to be involved in the binding which supports previous postulation of the involvement of these amino acid residues during tanning.