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Esterase

About: Esterase is a research topic. Over the lifetime, 7622 publications have been published within this topic receiving 168270 citations.


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Journal ArticleDOI
TL;DR: The results indicated that the xylanolytic-cellulolytic enzyme system of this bacterium exists as multienzyme complexes.
Abstract: A facultatively anaerobic bacterium, Paenibacillus curdlanolyticus B-6, isolated from an anaerobic digester produces an extracellular xylanolytic-cellulolytic enzyme system containing xylanase, β-xylosidase, arabinofuranosidase, acetyl esterase, mannanase, carboxymethyl cellulase (CMCase), avicelase, cellobiohydrolase, β-glucosidase, amylase, and chitinase when grown on xylan under aerobic conditions. During growth on xylan, the bacterial cells were found to adhere to xylan from the early exponential growth phase to the late stationary growth phase. Scanning electron microscopic analysis revealed the adhesion of cells to xylan. The crude enzyme preparation was found to be capable of binding to insoluble xylan and Avicel. The xylanolytic-cellulolytic enzyme system efficiently hydrolyzed insoluble xylan, Avicel, and corn hulls to soluble sugars that were exclusively xylose and glucose. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of a crude enzyme preparation exhibited at least 17 proteins, and zymograms revealed multiple xylanases and cellulases containing 12 xylanases and 9 CMCases. The cellulose-binding proteins, which are mainly in a multienzyme complex, were isolated from the crude enzyme preparation by affinity purification on cellulose. This showed nine proteins by SDS-PAGE and eight xylanases and six CMCases on zymograms. Sephacryl S-300 gel filtration showed that the cellulose-binding proteins consisted of two multienzyme complexes with molecular masses of 1,450 and 400 kDa. The results indicated that the xylanolytic-cellulolytic enzyme system of this bacterium exists as multienzyme complexes.

142 citations

Journal ArticleDOI
TL;DR: The studies suggest that the α2-macroglobulin is a major plasma inhibitor of kallikrein and provide a new example of an interrelationship between the coagulation, fibrinolytic, and kall Kikrein enzyme systems.
Abstract: Activation of plasma kallikrein arginine esterase activity by kaolin resulted in peak activity at 1 min of incubation and a 50% reduction in activity at 5 min in normal plasma, and 30% reduction in the plasma of patients with hereditary angioneurotic edema who lacked the C1 inactivator. The peak esterolytic activity was inhibited by soybean trypsin inhibitor whereas the 5 min activity was resistant to this inhibitor. Acid treatment of normal and hereditary angioneurotic edema plasma destroyed the factor responsible for the fall in esterase activity at 5 min and the factor which rendered the esterase resistant to soybean trypsin inhibitor. Purified alpha(2)-macroglobulin inhibited approximately 50% of the TAMe esterase activity of purified plasma kallikrein without changing its activity toward basic amino acid esters. The interaction between the alpha(2)-macroglobulin and kallikrein resulted in alterations in the gel filtration chromatographic pattern of the TAMe esterase and biologic activity of kallikrein, indicating that kallikrein was bound to the alpha(2)-macroglobulin. The TAMe esterase activity of this complex, isolated by column chromatography, was resistant to C1 inactivator and SBTI. Studies of incubation mixtures of kallikrein, alpha(2)-macroglobulin and C1 inactivator suggested that these inhibitors compete for the enzyme, and that the alpha(2)-macroglobulin partially protects the esterase activity of kallikrein from C1 inactivator. The alpha(2)-macroglobulin isolated from kaolin-activated plasma possessed 240 times the esterolytic activity of the alpha(2)-macroglobulin purified from plasma treated with inhibitors of kallikrein and of its activation. The alpha(2)-macroglobulin blocked the uterine-containing activity and vascular permeability-inducing effects of plasma kallikrein. These studies suggest that the alpha(2)-macroglobulin is a major plasma inhibitor of kallikrein and provide a new example of an interrelationship between the coagulation, fibrinolytic, and kallikrein enzyme systems.

142 citations

Journal ArticleDOI
TL;DR: Esterase activity was present in all subcellular fractions but most enzyme activity was found in the 100,000 ×g defatted supernatant fraction, which produced no differences in esterase activity over saline-injected controls.
Abstract: Cholesterol esterase activity was measured in luteinized ovarian tissue from immature superovulated rats. Enzyme activity was determined from the rate of appearance of lmitic acid-l-14C, hydrolyzed from a cholesteryl pa lmitate-l-14C substrate during 30 min of incubation at 37 C. Direct proportionality of incubation time with hydrolysis and enzyme concentration with reaction velocity was established for the enzyme assay system. Esterase activity was present in all subcellular fractions but most enzyme activity was found in the 100,000 ×g defatted supernatant fraction. LH 10 ng), administered iv 1 hr before sacrifice, resulted in a highly significant (p <.001) increase esterase activity over saline-injected controls. suspension of 1500 ×g pellet from homogenized luteal tissue was incubated in the presence of ATP (1.7×10-3M), theophylline (10-3M) and LH or saline; the supernatant fractions from these incubations when added to the usual 100,000 ×g supernatant fraction produced no differences in esterase acti...

141 citations

Journal ArticleDOI
TL;DR: Pseudomonas diminuta strain MG hydrolyzes parathion to diethylthiophosphoric acid and p-nitrophenol and the esterase responsible for this reaction is encoded by a gene located on a plasmid termed pCMS1, which resulted in the isolation of transconjugants that exhibitedParathion hydrolase activity.
Abstract: Pseudomonas diminuta strain MG hydrolyzes parathion to diethylthiophosphoric acid and p-nitrophenol. The esterase responsible for this reaction is encoded by a gene located on a plasmid termed pCMS1. The gene was cloned into plasmid pBR322 and the broad host range cloning vector pKT230. Enzyme activity was detected in Escherichia coli strains that contained the recombinant plasmids. A 1.5 kilobase BamHI fragment with single restriction sites for SalI, PstI and XhoI was shown to direct the synthesis of the enzyme. The 1.5 kilobase BamHI fragment was inserted into the high expression vector pUC7, and the resulting recombinant, pCMS40, was used to construct pKT230 derivatives containing the parathion hydrolase gene. Subsequent transfer of the recombinant plasmids into a cured derivative of P. diminuta MG and a p-nitrophenol-utilizing strain of Pseudomonas resulted in the isolation of transconjugants that exhibited parathion hydrolase activity. The highest enzyme activity was observed with P. diminuta MG.

141 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202391
2022209
202183
2020112
2019107
2018129