摘要：

1. 1.A collagenolytic enzyme has been isolated from the culture medium of tissue cultures of normal human skin but not from tissue extracts. The enzyme is capable of reducing the specific viscosity of native collagen at 28° and neutral pH in addition to lowering the denaturation temperature by approximately 5° without altering its helical content. 2. 2.Enzymatic attack on the collagen molecule results in the appearance of new, faster moving bands on disc electrophoresis. Electron micrographs of segment long spacings prepared from the enzyme-collagen reaction mixtures reveal the presence of an "A" end fragment (TC A) 75% the length of the collagen molecule and a "B" fragment (TC B) representing the remaining one-quarter. 3. 3.Human skin collagenase also acts on collagen in the native fibrillar form at 37° with a pH optimum of 7 to 8. No enzyme activity is present below pH 5.0, above pH 8.0 activity falls off markedly. The enzyme is inhibited by low concentrations of EDTA, cysteine and human serum but not by soybean trypsin inhibitor.

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