High molecular mass type IV collagen‐specific metalloprotease from human carcinoma tissue

Abstract
A protease degrading type IV collagen was purified more than 8000‐fold from human stomach carcinoma tissue. This protease degraded type IV collagen, while type I, II, III and V collagen, laminin, fibronectin, casein, albumin and hemoglobin were not affected. This enzyme had a pH optimum of pH 7.0–8.0 and was inhibited completely by EDTA and o‐phenanthroline, but not by seryl, thiol and carboxyl protease inhibitors. Furthermore, the molecular mas of this enzyme was estimated to be 1 MDa by Sepharose 6B column and HPLC‐gel filtration. The molecular mass and substrate specificity of this metalloprotease from human carcinoma tissue indicate it to be a new protease.