both peaks contained type i collagenous proteins since on chromatography on carboxymethylcellulose , after limited pepsin proteolysis , both peaks contained alpha1 and alpha2 chains of collagen in a 2:1 ratio , and cyanogen bromide peptide maps of the 14c-labeled protein in both peaks were similar to cyanogen bromide peptide maps derived from authentic type i collagen .
C0009325
collagen
C0041455
type i collagen