Evidence for a Faster Degradation of an Atypical Hydroxyproline and Hydroxylysine Deficient Collagen Formed under the Effect of 2,2′‐Dipyridyl

1 Chick embryo skin slices were incubated with [ 14 C]proline without and in the presence of 1 mM 2,2′‐dipyridyl. Collagen was isolated and digested with collagenase. The kinetics of the splitting off of small radioactive fragments showed a more rapid degradation of the undenatured hydroxyproline and hydroxylysine deficient collagen which had been formed in the presence of 2,2′‐dipyridyl, compared to the control sample. No differences in the rate of digestion have been found between heat denatured control and atypical collagen. 2 In parallel experiments the rate of collagenase degradation of proline rich Ascaris cuticle collagen was several times greater than that of calf skin collagen. 3 Skin slices incubated simultaneously with [ 14 C]glutamic acid and 0.5 mM dipridyl showed more radioactive proline than did control samples. This is further evidence for increased degradation of atypical collagen because under these experimental conditions the metabolism of non‐collagenous protein was the same in control and dipyridyl treated samples. It is apparent that hydroxyproline and hydroxylysine decicient collagen is more susceptible to the action of collagenase and other tissue proeases.