Cleavage of type I procollagen by C- and N-proteinases is more rapid if the substrate is aggregated with dextran sulfate or polyethylene glycol.

The enzymes procollagen C- and N-proteinases specifically cleave carboxyl- and amino-terminal propeptides of procollagens. After cleavage of the propeptides, the resulting collagens self-assemble into fibrils. In most previous experiments with the enzymes, the substrate was monomeric type I procollagen.

Cadmium ions inhibit procollagen C-proteinase and cupric ions inhibit procollagen N-proteinase.

Procollagen C- and N-proteinases specifically cleave the C- and N-terminal extension propeptides of type I, II and III procollagen molecules. The collagen molecules generated by the enzymes self-assemble into collagen fibrils. We previously observed the inhibition of these enzymes purified from chick tendons by several divalent metals.