Proteolytic enzymes

About: Proteolytic enzymes is a research topic. Over the lifetime, 23096 publications have been published within this topic receiving 835544 citations.

Assay of coagulation proteases using peptide chromogenic and fluorogenic substrates.

Abstract: Publisher Summary Amino acid chromogenic and fluorogenic substrates have been used for many years for assaying proteases. The sensitivity of the assay procedures that employ these substrates and the convenience of spectrophotometric or fluorometric measurements has led to their widespread use. Most of the early amino acid chromogenic and fluorogenic substrates are highly selective for the primary specificity-determining (P1) amino acid; thus substrates such as benzoylarginine-p-nitroanilide, for assaying trypsin-like proteases, as well as aromatic amino acidp-nitrophenyl esters for chymotrypsin-like proteases, have been extensively investigated and employed for routine proteolytic enzyme assay. The recognition that both the selectivity of many proteases and their catalytic efficiency depend on interactions with subsite amino acids in the peptide substrate coupled with the availability of amino acid sequences around the cleavage sites in several zymogens of the coagulation and fibrinolytic systems has led to the synthesis and commercial availability of a variety of peptide chromogenic and fluorogenic substrates with much greater selectivity than the single amino acid chromogenic and fluorogenic substrates.

Inflammatory mediators in the pathogenesis of periodontitis

Abstract: Periodontitis is a chronic inflammatory condition of the periodontium involving interactions between bacterial products, numerous cell populations and inflammatory mediators. It is generally accepted that periodontitis is initiated by complex and diverse microbial biofilms which form on the teeth, i.e. dental plaque. Substances released from this biofilm such as lipopolysaccharides, antigens and other virulence factors, gain access to the gingival tissue and initiate an inflammatory and immune response, leading to the activation of host defence cells. As a result of cellular activation, inflammatory mediators, including cytokines, chemokines, arachidonic acid metabolites and proteolytic enzymes collectively contribute to tissue destruction and bone resorption. This review summarises recent studies on the pathogenesis of periodontitis, with the main focus on inflammatory mediators and their role in periodontal disease.

Structural and immunological similarities between simian sarcoma virus gene product(s) and human platelet-derived growth factor

Abstract: The predicted amino acid sequence of the simian sarcoma virus (SSV) transforming gene product, p28SIS, closely corresponds to that of human platelet-derived growth factor (PDGF). We demonstrate that p28SIS rapidly undergoes a series of discrete processing steps including dimer formation and proteolytic digestion to yield molecules structurally and immunologically resembling biologically active PDGF.

Degradation of connective tissue matrices by macrophages. I. Proteolysis of elastin, glycoproteins, and collagen by proteinases isolated from macrophages.

Abstract: We have investigated the ability of neutral and lysosomal enzymes of mouse macrophages to degrade the insoluble extracellular matrices secreted by smooth muscle cells, endothelial cells, and fibroblasts. Matrices produced by smooth muscle cells contained glycoproteins, elastin, and collagens, but matrices of endothelial cells and fibroblasts contained no elastin. Sequential enzyme digestion of residual matrix revealed that plasmin, a product of macrophage plasminogen activation, degraded 50-70% of the glycoprotein in the matrices but did not degrade the elastin or the collagens. Purified macrophage elastase degraded glycoprotein and elastin components but had no effect on the collagens. The rate of elastin degradation by macrophage elastase was decreased in the presence of the glycoproteins. In contrast, human granulocyte elastase effectively degraded the matrix glycoproteins, elastin, and, to a lesser extent, collagens, Mammalian collagenase degraded only collagens. Conditioned medium from resident and inflammatory macrophages, containing mixtures of the secreted proteinases, degraded the glycoprotein and elastin components of the matrices. However, conditioned medium was less effective in degrading matrix than comparable amounts of purified macrophage elastase because > 90% of the elastase in the medium was in a latent form. Inclusion of plasminogen in the assays accelerated degradation. In the presence of plasminogen, glycoproteins were degraded readily by medium from P388D1, pyran copolymer-, thioglycollate-, and periodate-elicited macrophages and, to a lesser extent, by medium from endotoxin-elicited and resident macrophages; medium from P388D1, thioglycollate-, and periodate-elicited macrophages was most effective in elastin degradation, and resident, endotoxin-elicited and pyran copolymer-elicited macrophages degraded almost no elastin. The macrophage cathepsins D and B degraded all the matrix components at an optimum pH of 5.5 and acted with the secreted neutral proteinases to degrade the connective tissue macromolecules to amino acids and oligopeptides. These data indicate that macrophages at inflammatory sites contain and secrete proteolytic enzymes that could degrade the extracellular matrix.

Matrix Metalloproteinases (MMP-2 and MMP-9) of the Oral Cavity: Cellular Origin and Relationship to Periodontal Status:

Abstract: Proteolytic enzymes released by the host cells are associated with the tissue destruction in periodontal diseases. Matrix metalloproteinases (MMPs) have the primary role in this process, since, in concert, they can degrade most of the extracellular matrix components. In the present study, we investigated MMP-2 and MMP-9 in oral fluids of healthy subjects and periodontitis patients and the contributions of different oral cells to the enzyme production. The enzymograms revealed that the main gelatinase in oral rinses, crevicular fluid, and whole saliva migrated at 92 kDa. Activity was also detected at 200 kDa and 130 kDa and minor activity at 86 kDa, 72 kDa, and 40 kDa. Traces of gelatinolytic activity were also detected in pure parotid secretions. The 92-kDa enzyme was identified to MMP-9 and the 200-kDa gelatinase to MMP-2, by means of specific anti-72-kDa antiserum. Gingival keratinocytes produced mainly MMP-9, while gingival and granulation tissue fibroblasts expressed MMP-2. Glandular tissue contained mainly MMP-9, and mRNA for MMP-9 was also found in acinar epithelial cells. Periodontitis patients had significantly higher levels of MMP-9 than healthy subjects. Also, MMP-2 was elevated in periodontitis patients. Periodontal treatment reduced the amount of gelatinases dramatically. This study shows that gelatinases are produced by various cells in the oral cavity. The amount of gelatinases is elevated during periodontal disease, while conventional periodontal treatment efficiently reduces the levels these enzymes. We suggest that MMP-2 and MMP-9 could participate in tissue destruction in periodontitis.