Detection of type V collagen-degrading enzyme activity in human liver.

Type V collagen-degrading enzyme activity was detected as a metalloprotease acting at neutral pH in the human liver. Type V collagen extracted from human placenta and labeled with [1-14C] acetic anhydride was used as the substrate in the assay. Four major degradation products with relatively high molecular weights were observed upon polyacrylamide gel electrophoresis of the incubation mixture of type V collagen and liver homogenate. The significance of the measurement of this enzyme activity was discussed in relation to the clarification of the mechanism of liver fibrosis.