Enzymes proteinase activity

Trypsin is a major proteolytic digestive enzyme and the identified endogenous ligand for proteinase-activated receptor 2 (PAR 2). 

Proteinases and antiproteinases are part of the normal protective and repair mechanisms in the lungs. The imbalance of proteinase-antiproteinase activity in COPD is a result of either increased production or activity of destructive proteinases or inactivation or reduced production of protective antiproteinases. AAT (an antiproteinase) inhibits trypsin, elastase, and several other proteolytic enzymes. Deficiency of AAT results in unopposed proteinase activity, which promotes destruction of alveolar walls and lung parenchyma, leading to emphysema. 

Female NMRI mice were exposed to 100 ppm of hydrogen sulfide for 2 hours at 4-day intervals excitement was observed (Savolainen et al. 1980). Exposure also resulted in decreased cerebral ribonucleic acid (RNA), decreased orotic acid incorporation into the RNA fraction, and inhibition of cytochrome oxidase. An increase in the glial enzyme marker, 2, 3 -cyclic nucleotide-3 -phosphohydrolase, was seen. Neurochemical effects have been reported in other studies. Decreased leucine uptake and acid proteinase activity in the brain were observed in mice exposed to 100 ppm hydrogen sulfide for 2 hours (Elovaara et al. 1978). Inhibition of brain cytochrome oxidase and a decrease in orotic acid uptake were observed in mice exposed to 100 ppm hydrogen sulfide for up to 4 days (Savolainen et al. 1980). 

In an earlier report (J>), the decay of healthy yam tubers during storage was shown to be a result of catabolism of its proteins by an active a-glutamyl transpeptidase. There is also some alkaline proteolytic activity in the yam tuber (6), but little information is available on individual enzymes of the purine degradative pathway and on the properties of an alkaline proteinase that may function in yams during storage. This report describes the interrelation of five enzymes of ureide metabolism in fresh and stored yams, the release of ammonia in vitro by three of the enzymes that may provide an environment for alkaline proteinase activity in vivo, and the in vitro properties of an... 

Table 4. Substrate Specificity of Yam Tuber Alkaline Proteinase (Activity mg protein hydrolyzed)/10 mg enzyme/2hr).

Garcfa-Carreno, F.L., Herandez-Cortes, M.P., and Haard, N.F. 1994. Enzymes with peptidase and proteinase activity from the digestive systems of freshwater and a marine decapod. J. Agric. Food Chem. 42 1456-1461. 

Figure B3.1.2 Native discontinuous polyacrylamide gels activity stained for proteinases. (A) Gel stained with Coomassie brilliant blue for total protein. (B) Gel assayed for proteinase activity using casein as a substrate. Samples are enzyme extracts of hepatopancreas from four shrimp species. Lane 1, molecular weight markers Lane 2, Rcaliforniensis Lane 3 R vannamei Lane 4, Rpaulensis, Lane 5, P. schmitti.

Sekine, H. (1973). Neutral proteinases II of Aspergilus sojae an enzyme specifically active on protamine and histone. Agric. Biol. Chem., 37, 1765-1767. 

Mullally, M.M., Meisel, H., and FitzGerald, R.J. 1997b. Angiotensin-I-converting enzyme inhibitory activities of gastric and pancreatic proteinase digests of whey proteins. Int. Dairy J. 7, 299-303. 

In our initial research on semisynthetic enzymes, we examined briefly the modification of the serine proteinase a-chymotrypsin, perhaps the best understood of the proteolytic enzymes. A logical choice as a residue for alkylation in the active site of a-chymotrypsin is His-57. However, an examination of a three-dimensional model (Lab Quip) of chymotrypsin in which coenzyme analogs were covalently attached to His-57 suggested strongly that such modifications would block completely the enzyme s active site region and that the probability of new reactions being catalyzed by the modified enzyme would be low. Another possible site of modification of chymotrypsin that could be considered was Met-192. This residue, located on the periphery of the... 

In addition to carboxylesterases, another hydrolyzing enzyme, proteinase, is also involved in resistance. Oppert et al. (1997) showed that two Bt-resistant strains of the Indian meal moth, Plodia interpunctella, lack a major gut proteinase that activates Bt protoxins as compared with susceptible strains. The absence of this enzyme is genetically linked to larval susceptibility to the toxin. 

Zymography A method for detecting enzyme activity on a matrix, usually a polyacrylamide gel or agarose gel after electrophoretic separation. See Frederiks, W.M. and Mook, O.R., Metabolic mapping of proteinase activity with emphasis on in situ zymography of gelatinases review and protocols, J. Histochem. Cytochem. 52, 711-722, 2004 Lombard, C., Saulnier, J., and Wallach, J., Assays of matrix metalloproteinases (MMPs) activities a review, Biochemie 87, 265-272, 2005. 

Studies of proteinase activities comprise some of the most important current research efforts in the field of theoretical enzyme mechanisms. Results from crystallography and kinetics in the 70 s and 80 s paved the way for such theoretical studies, mainly of the serine proteinase family. Such studies are extending nowadays, as more structures of proteinases are solved with high resolution and more detailed kinetic studies are conducted. But, while earlier structural results were available for the native structures alone, recent crystallographic evidence is available for complexes with peptide analogs, with intermediate analogs and with mutant enzymes. When these structural studies are coupled with results of kinetic research, a large database is formed for the theoretician to consider as a basis for construction, simulation and analysis by computer models. 

PlaqueniP hydroxychloroquine, plasma thromboplastin component factor IX. plasminogen activator inhibitor (proteinase inhibitor PAI) is a peptide containing 376-379 amino acid residues, found in 3 forms. It is an ENZYME INHIBITOR actively involved in the control of haemostatic blood clotting factors. Increased levels are found in metastases it is a possible diagnostic agent and target for anticancer chemotherapy, plasmin fibrinolysin. 

Proteinase precursors, also called zymogens or proenzymes, become catalytically active enzymes upon specific proteolytic cleavage. The precursor molecules circulate as inactive forms that do not exhibit enzymatic activity. The activation processes are irreversible. Extensive structural similarities are found among all proteinase precursors. The regions of the molecules that express proteinase activity after activation are found in the C-terminal one-half to one-third of each molecule. The portion of each precursor... 

The reaction of the proteinase with the inhibitor occurs at a basic residue (Arg or Lys residue) in a loop that extends away from the globular inhibitor molecule. This basic residue, called the reactive site residue, is locked in the proteinase active site as the acyl enzyme. The reactive site... 

Several homogeneous synthetic artificial enzymes " and catalytic antibod-igsi05,i06 proteinase activity have been reported. The monoclonal catalytic antibody prepared with a phosphinate hapten exhibited optimum activity at pH 9.5. The measured with an amide substrate at pH 9 and 37 °C was 1.65 x 10" s" Thus, the half-life is 49 days when the substrate is fully complexed to the active site of the catalytic antibody. 

From Sephadex G-10 and G-15 gel filtration, the molecular weight of CF was calculated as about 700 daltons (16). To obtain further information about the chemical nature of CF, the active CF fraction, isolated after Sephadex G-10 gel filtration, was treated with different enzymes. Enzymes proteinase K, cellulase, a and / amylase did not reduce the CF activity (data not shown). 

Standard experiments to determine the method by which schumannificine exerted its effect revealed that it prevented the infection of the host cell by the HIV by binding to the gpl20 on the viral coat. Some glycosidase inhibition was also noted which may contribute to the antiviral effect since this enzyme is important in the formation of new viral material after infection and replication of viral DNA in the host cell [43]. Schumannificine did not possess any reverse transcriptase or proteinase activity. 

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