The existing forms of collagenase in the human uterine cervix

The existing forms of collagenase [EC 3.4.24.7] in the human uterine cervix were examined. The latent collagenase extracted by homogenization in 0.25% Triton X-100 containing 0.01 M CaCl2 was indicated to be a complex of collagenase with alpha 2-macroglobulin by the behavior of the fraction of this enzyme before and after treatment with NaSCN on Sephadex G-150 column chromatography and an immunodiffusion method. The active collagenase was extracted by rehomogenization in 50 mM Tris-HCl buffer, pH 7.4, containing 0.1 M M CaCl2 from the insoluble residue at 0 degrees C. Another latent collagenase was extracted from the insoluble fraction in the same buffer by heating at 60 degrees C for 4 min and this enzyme was activated by 4-aminophenylmercuric acetate or trypsin. The molecular weights of the active and the latent forms were approximately 7.3 x 10(4) and 9.4 x 10(4), respectively. This indicates that the latency is due to the formation of a low molecular weight inhibitor enzyme complex. These results clarified that the human uterine cervix contains three existing forms (alpha 2-macroglobulin complex, active form and low molecular weight inhibitor complex) of collagenase under these experimental conditions.