Metal binding peptide inhibitors of vertebrate collagenase

A series of metal binding peptide analogues of the C-terminal sequence of collagen adjacent to its known site of cleavage by vertebrate collagenases has been synthesized by solid phase methods and tested as inhibitors both of collagenolysis and of hydrolysis of the model substrate DNP-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg by tadpole backskin collagenase. The peptide analogue inhibitors have the general structure R-Ala-Gly-Gln-D-Arg-NH 2. Using an HPLC assay system, I 50 values of 70 μM, 50 μM and 10 μM were obtained for the three most potent inhibitors for which R = HSCH(CH 2C 6H 5)CO-, HSCH 2CH(NH 2CO- and HSCH(CH 2CH(CH 3) 2)CO-, respectively, when the above octapeptide was used as substrate. In contrast, an I 50 value of 3 mM was found for cysteine under the same conditions. The mercaptophenylalanyl derivative was also highly effective in inhibiting collagen degradation. Using calf skin collagen as substrate, inhibition was obtained at concentrations of peptide analogue below 10 μM.