QUANTITATIVE-ANALYSIS OF CYANOGEN BROMIDE-CLEAVED PEPTIDES FOR THE ASSESSMENT OF TYPE-I-TYPE-II COLLAGEN RATIOS IN EQUINE ARTICULAR REPAIR TISSUE

Cyanogen bromide was used to solubilise and specifically fragment puri fied equine Type I and II collagen and equine articular surface repair tissue. The resultant peptides were separated by sodium dodecyl sulph ate-polyacrylamide gel electrophoresis and quantified by densitometric scanning. Measurement of the relative amounts of the peptides alpha 2 (I) CB3, 5 and alpha 1(II)CB10 provided an accurate method of establis hing the ratio of Type I to Type II collagen in mixtures of purified e quine collagens. The method was sensitive to 6% Type II collagen when the band areas were corrected for peptide molecular weight and the num ber of chains in the parent tropocollagen molecule which contain that particular peptide. Use of this technique showed that repair tissue in full thickness osteochondral defects in the dorsodistal margins of th e intermediate carpal bones of ponies did not contain detectable amoun ts of Type II collagen 11 weeks after defect induction.