Heterogeneity among human collagenases demonstrated by monoclonal antibody that selectively recognizes and inhibits human neutrophil collagenase.

The heterogeneity of human collagenases has been examined using a monoclonal antibody to neutrophil collagenase. This antibody inhibited collagenase activity and, when covalently coupled to Sepharose, bound both latent and active enzyme. Although human neutrophil collagenase was inhibited by the antibody, the activity of human skin and rheumatoid synovial collagenase was not significantly diminished in the presence of the antibody. Competitive inhibition studies also differentiated between these collagenases. Only human neutrophil collagenase effectively blocked the antibody in a competitive enzyme-linked immunosorbent assay while skin and rheumatoid synovial collagenase again failed to interact with the antibody. The unequivocal recognition of neutrophil collagenase as an immunologically distinct entity from other collagenases supports the hypothesis that neutrophil collagenase is a separate gene product from fibroblast or synovial collagenase.

Kinetics of the inhibition of leukocyte elastase by the bronchial inhibitor.

The rate constant for the association between human leukocyte elastase (EC 3.4.21.11) and human bronchial inhibitor has been determined by competition experiments with alpha 1-proteinase inhibitor. This constant (1.1.10(7) M(-1) . s(-1)) is 6-times lower than that for the association of leukocyte elastase and alpha 1-proteinase inhibitor. The latter inhibitor is able to dissociate the leukocyte elastase-bronchial inhibitor complex with a rate constant 1.3.10(-4) s-1. The equilibrium dissociation constant Ki of the complex is 1.2.10(-11) M. The physiopathological significance of these constants is discussed.

Preferential binding of collagenase to alpha 2-macroglobulin in the presence of the tissue inhibitor of metalloproteinases.

The binding of collagenase to both alpha 2-macroglobulin and the tissue inhibitor of metalloproteinases was studied using purified materials. Collagenase bound preferentially to alpha 2-macroglobulin although no transfer of collagenase to alpha 2-macroglobulin occurred if the enzyme was first mixed with the tissue inhibitor of metalloproteinases. The sequences of amino acids in both inhibitors likely to be responsible for the binding of collagenase are discussed and compared to the cleavage site in the collagen molecule.

Purification and properties of a collagenase inhibitor from cultures of bovine aorta.

Bovine medial explants in culture synthesize a potent inhibitor of mammalian collagenase but not of bacterial collagenase. This inhibitor has been partially purified and has an apparent molecular weight of 45,000. It is a glycoprotein and is stable to heat, trypsin, acid and mercurials. Inhibitory activity is destroyed on reductive alkylation. The inhibitor interacts with collagenase and this interaction leads to the loss of enzymatic activity. This inhibitor may play a physiological role in the control of collagen degradation in blood vessels.

Inhibition of production and action of tissue metalloproteinases.

There is strong evidence that a family of MPs involved in the resorption of the matrices of connective tissues. These proteinases seem to be induced by specific stimuli whereas cells and tissues normally produce a specific inhibitor, TIMP. In many experimental situation there is good evidence that increased resorption is correlated with an imbalance of TIMP over active MPs. Current research is aimed at finding better compounds than corticosteroids to increase the balance of TIMP over MPs.

Purification of guanine deaminase inhibitor from human brain.

A procedure for the purification of guanine deaminase inhibitor from human brain mitochondria is described. The inhibitor was enriched about 150-fold with recoveries of over 65%. It is nondialyzable, insoluble in water, and stable for over 30 days at -16 degrees C. However, the protein is completely inactivated at 50 degrees C in 5 min. The purified protein also inhibits the activities of a number of other enzymes.

Antitrypsin activity and enzyme inhibitors in the rheumatoid joint.

Proteolytic enzyme inhibitor activity has been measured in the rheumatoid knee by 2 different techniques. The inactivation rate of trypsin injected into the joint in 13 patients was compared with synovial fluid levels of alpha-1-antitrypsin (apha 1AT), alpha-2-macroglobulin (alpha 2M) and trypsin inhibitory capacity (TIC). The lack of correlation and the fact that an inverse relationship was shown between the T1/2 to inactivation and joint damage suggests that additional mechanisms are involved in the inactivation of destructive enzymes. Serum levels of alpha 1AT and TIC were elevated in 36 rheumatoid arthritis (RA) patients when compared with control values and RA synovial fluid inhibitor levels elevated by comparison with osteoarthritic figures. The synovial fluid alpha 1AT and TIC correlated with the activity of the lysosomal enzyme beta-acetyl glucosaminidase (beta AGA) but only trace amount of neutral protease activity was detected probably because of the large concentration of inhibitors present. The deficient Pi phenotype MZ was rarely encountered.