Preferential binding of collagenase to α2-macroglobulin in the presence of the tissue inhibitor of metalloproteinases

The binding of collagenase to both α2-niacroglobulin and the tissue inhibitor of metalloproteinases was studied using purified materials. Collagenase bound preferentially to α2-macroglobulin although no transfer of collagenase to α2-macroglobulin occurred if the enzyme was first mixed with the tissue inhibitor of metalloproteinases. The sequences of amino acids in both inhibitors likely to be responsible for the binding of collagenase are discussed and compared to the cleavage site in the collagen molecule.