Characterization of gelatinases in human placenta

Matrix metalloproteinases were extracted from human placenta. Gelatin zymograms showed four bands with gelatinase activity. These four bands were detected at Mr 72,000, 92,000, 130,000, and 210,000 respectively. Reduced and alkylated samples were detected at Mr 72,000 and 92,000. Immunoblotting analysis showed that the enzymes of Mr 130,000 and 210,000 were derived from gelatinase B (EC 3.4.24.35). Also, reduced gelatinase was activated by 4-aminophenylmercuric acetate more readily than a nonreduced gelatinase. This indicates that human placental gelatinases are stabilized by the tissue inhibitor of metalloproteinases.