Proteolytic enzymes

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

Pseudomonas aeruginosa elastase and its role in pseudomonas infections

Abstract: Most strains of Pseudomonas aeruginosa produce three proteases with broad substrate specificities. One of these enzymes has elastolytic activity (P. aeruginosa elastase). This elastase has tissue-damaging activity and is capable of degrading various plasma proteins such as immunoglobulins, coagulation and complement factors, and alpha-proteinase inhibitor. There is evidence for a role of elastase in localized infections such as experimental pseudomonas keratitis, pneumonia, and burn infection. Once colonization and invasion has occurred and septicemia has been established, these enzymes are probably less important. Elastase is probably best classified as a virulence-enhancing factor in certain types of infections.

Insertional mutagenesis of the lon gene in Escherichia coli: lon is dispensable.

Abstract: The lon gene of Escherichia coli codes for an ATP-dependent protease. Mutations in lon cause a defect in the intracellular degradation of abnormal and mutant proteins and lead to a number of phenotypic changes, such as UV sensitivity and overproduction of capsular polysaccharide. We have isolated lambda transducing phage carrying the lon gene and used the lon phage as a target for insertional mutagenesis by a defective transposon Tn10 to produce lon::delta 16 delta 17Tn10 derivatives. The delta 16 delta 17Tn10 (hereafter called delta Tn10) elements were inserted at sites throughout the lon gene and disrupted the coding region between 15 and 75% of the distance from the amino-terminal end. Radioactive labeling of proteins in vivo in cells infected with different lambda lon::delta Tn10 phage demonstrated that the insertions resulted in the synthesis of truncated Lon proteins. The lon::delta Tn10 mutations, when crossed from the phage into the bacterial chromosome, abolished the synthesis of intact Lon protein, as assayed by antibody on Western blots. An analysis of the protein-degradative ability of lon::delta Tn10 cells suggests that although the insertions in lon caused a reduction in ATP-dependent protein degradation, they did not completely eliminate such degradation either in vivo or in vitro. The lon::delta Tn10 mutations and a lon deletion retaining only the amino-terminal 25% of the gene did not affect the energy-dependent degradation of proteins during starvation and led to only a 40 to 60% reduction in the ATP-dependent degradation of canavanine-containing proteins and puromycyl peptides. Our data provide clear evidence that energy-dependent proteolytic enzymes other than Lon exist in E. coli.

The Clinical Relevance of Stromal Matrix Metalloproteinase Expression in Ovarian Cancer

Abstract: Purpose: Matrix metalloproteinases (MMP) are proteolytic enzymes implicated in cancer progression and metastasis. We sought to determine the role of epithelial (tumor cell–derived) and stromal (host-derived) expression of MMPs in predicting the clinical outcome of patients with epithelial ovarian cancer (EOC). Experimental Design: MMP-2, MMP-9, and membrane type 1 (MT1)-MMP expression was evaluated using immunohistochemistry in 90 invasive EOCs, and samples were scored for epithelial and stromal staining. Results were correlated with clinicopathologic characteristics using univariate and multivariate analyses. Results: High expression of MMP-2, MMP-9, and MT1-MMP in tumor epithelium was detected in 54%, 97%, and 100% of cases, and in stromal compartments, in 38%, 70%, and 38% of cases, respectively. High stromal expression of MMP-2, MMP-9, and MT1-MMP was significantly associated with aggressive features such as high stage, high grade ascites, and positive lymph node status. Kaplan-Meier analysis showed that high epithelial and stromal expression of MMP-2, MMP-9, and MT1-MMP were each significantly associated with shorter disease-specific survival (DSS; P P P = 0.01) and MT1-MMP ( P = 0.04), strong epithelial MT1-MMP ( P = 0.01) and high stage ( P = 0.04) were independent predictors of poor DSS. Conclusions: Overexpression of stromal MMP-9 and MT1-MMP is independently associated with shorter DSS in EOC. Thus, host-derived MMPs are valuable predictors of clinical outcome in EOC.

Ultra fast trypsin digestion of proteins by high intensity focused ultrasound.

Abstract: Proteolytic digestion of proteins in seconds under an ultrasonic field provided by high-intensity focused ultrasound (HIFU) has been achieved. Successful in-solution and in-gel tryptic digestion of proteins in 60 s or less was demonstrated by either MALDI-TOF mass spectrometry or liquid chromatography-electrospray ion trap mass spectrometry (RP-HPLC-ESI-IT-MS/MS). The efficiency of this new procedure for protein digestion compared favorably with those attained using conventional overnight incubation methods. The performance of the method was also demonstrated by the specific identification of three proteins in a whole proteome in less than 1 h. The method greatly reduces the time needed for protein digestion, is of easy implementation, environmental friendly, and economic. Adaptation of this method to on-line procedures and robotic platforms could have promising applications in the proteomics field.

Beneficial effects of cholecystokinin-receptor blockade and inhibition of proteolytic enzyme activity in experimental acute hemorrhagic pancreatitis in mice. Evidence for cholecystokinin as a major factor in the development of acute pancreatitis.

Abstract: The effects of the cholecystokinin (CCK)-receptor antagonist proglumide, the protease inhibitor gabexate, and the hormones secretin and cholecystokinin-octapeptide (CCK-8) were studied in a model of acute hemorrhagic pancreatitis induced by feeding mice a choline-deficient, ethionine-supplemented (CDE) diet. Injections of gabexate and proglumide from initiation of CDE diet (before induction of pancreatitis) increased survival from 37% (diet alone) to 85 and 75%, respectively, and also ameliorated histological alterations and increases in serum amylase concentration and pancreatic activated trypsin. Secretin had no major beneficial effect. When proglumide or gabexate were given after induction of pancreatitis, proglumide still increased survival to 75%, whereas gabexate no longer did. Injection of nontoxic doses of CCK-8 before proglumide or gabexate injections completely abolished all beneficial effects and also increased the severity of pancreatitis due to CDE diet alone. Blockade of CCK receptors and early inhibition of protease activity may be beneficial in severe acute pancreatitis. Cholecystokinin appears to play a contributory role in the development of pancreatitis.