Dual effects of type II collagen on the degradation of type I collagen by tadpole collagenase.

Kinetic analysis of the degradation of mixtures of type I and type II collagens by tadpole collagenase was performed, using [14C]glycine-labeled type I collagen and [3H]acetylated type II collagen as substrates. The degradation rate of type I collagen was decreased in the initial stage of the reaction, then further slowed down giving a constant rate independent of both the amounts of enzyme and type II collagen. The effect of type II collagen on the degradation of type I collagen is two-fold. First, competitive inhibition manifested only in the initial stage of the reaction due to higher (about 4-fold) affinity of type II collagen for the enzyme than type I collagen. Second, interference in step(s) following the formation of enzyme-substrate complex.