1. Homogenates of @entity35 uteri removed 1 and 2 days post partum were centrifuged at 6000 g. Both pellets and supernatants degraded Azocoll, a general proteinase substrate, at pH 7.5. More than 80% of the total activity was in the pellet fraction. 2. Part of the pellet activity was in a latent form. Trypsin and @entity23792 (a @entity1432 -blocking agent) both activated this latent form, indicating that it is an enzyme--inhibitor complex. An endogenous @entity563 proteinase activated part of the latent enzyme during the assay. 3. The enzyme activity was low before parturition and after involution; it was highest during the first 2 days post partum, when the largest losses of uterine wet weight and matrix macromolecules occur. 4. Up to 70% of the enzyme in the pellets was extracted by heating at 60 degrees C for 4 min in 0.1 M-CaCl2/0.05 M-Tris/ @entity5828 , pH 7.5. Approx. 30% of the extracted enzyme was still latent. 5. The extracted enzyme was a metalloproteinase, since it was inhibited completely by @entity7437 , but not by inhibitors of @entity1432 or @entity563 proteinases. 6. The enzyme was further purified 15--30-fold by gel chromatography and precipitation with @entity4859 . The apparent molecular weight, estimated by gel filtration, was 24000 for the latent form and 12000 for the active form. The pH optimum was 7--7.5. 7. The enzyme also degraded cartilage proteoglycan. This activity was studied by viscometry and the products were analysed by analytical ultracentrifugation. The major product had a mol.wt. of approx. 100000. The sites of cleavage were in the protein core, since no free oligosaccharides were detected. 8. This neutral metalloproteinase is distinct from uterine collagenase and from a uterine metal-dependent endopeptidase that hydrolyses a heptapeptide related to collagen.

The extraction of a neutral metalloproteinase from the involuting XXXX uterus, and its action on cartilage proteoglycan.

@entity4859 :: ('CHEBI:62946', 'Chemical') :: ['(NH4)2SO4'] @entity23792 :: ('MESH:C010024', 'Chemical') :: ['4-aminophenylmercuric acetate'] @entity1432 :: ('CHEBI:29256', 'Chemical') :: ['thiol'] @entity5828 :: ('CHEBI:17883', 'Chemical') :: ['HCl'] @entity7437 :: ('MESH:C025205', 'Chemical') :: ['1,10-phenanthroline'] @entity563 :: ('CHEBI:17822', 'Chemical') :: ['serine'] @entity35 :: ('10116', 'Species') :: ['rat']
@entity35 :: (10116,Species) :: ['rat']
