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Showing papers on "Esterase published in 1979"


Journal ArticleDOI
TL;DR: Weight and time of moult during the last instar of the cabbage looper were examined and used to select last instars larvae that had similar rates of development and differed markedly from the α-naphthyl acetate esterase and protein content profiles.

103 citations


Journal ArticleDOI
TL;DR: The kinetic properties of two of the partially separated isoenzymes I and V of pig liver esterase were studied and offer explanations for many of the very complex and often controversial results formerly obtained with the heterogeneous pig liver Esterase.
Abstract: Three different subunits of highly purified pig liver esterase (EC 3.1.1.1) can be separated by analytical dodecyl sulfate electrophoresis, though their relative mobilities are very similar. The same subunit bands are obtained with microsomes, in which the esterases have been labeled with the specific active-site-directed inhibitor bis(4-nitro-[14C]phenyl)phosphate. The heterogeneity of the native trimeric enzyme is much more complex, as is demonstrated by isoelectric focussing and polyacrylamide gel electrophoresis. Fractions of esterase which were partially separated by preparative isoelectric focussing show differences in their subunit composition, their amino acid analyses, their tryptic peptide maps, and their C-terminal amino acids. From these experiments various features of the differing esterase subunits can be deduced. Based on the chemical results and on various experiments which did not indicate any secondary modification of the protein side-chains, the molecular basis of the esterase heterogeneity is discussed. We conclude that the native trimeric esterase is a mixture of numerous hybrids of at least three protein subunits with differing but closely related primary sequences. A comparison of the relative specificity of various preparations of pig liver microsomes indicates that genetic differences concerning the composition of liver esterase exist between individuals.

100 citations


Journal ArticleDOI
TL;DR: Evidence is consistent with a brief burst of juvenile hormone which occurs prior to pupation inducing the production of the second peak of juvenile hormones esterase activity.

85 citations


Journal ArticleDOI
TL;DR: An endoproteolytic enzyme of Escherichia coli, designated protease III, has been purified about 9,600-fold to homogeneity with a 6% yield and is very sensitive to metal-chelating agents and reducing agents.

81 citations


Journal ArticleDOI
TL;DR: In this article, mouse sternomastoid muscles were incubated with diisopropylfluorophosphate (DFP) in vivo, and the time course of recovery was studied using histochemistry, EM autoradiography and physiology.
Abstract: Mouse sternomastoid muscles were incubated with diisopropylfluorophosphate (DFP) in vivo, and the time course of recovery was studied using histochemistry, EM autoradiography and physiology. We found that: (1) the ability of the muscle to sustain tetanus in response to nerve stimulation is eliminated when the esterases at the neuromuscular junctions are saturated with DFP. This ability is regained partially when less than 10% of the DFP-binding sites have recovered. (2) There is a positive correlation between the frequency of stimulation at which the tetanic response can be maintained and the extent of acetylcholinesterase (AChE) recovery. (3) Tetanic responses at fusion frequency (about 100 Hz) appear indistinguishable from controls with only about 25% of normal AChE. (4) Butyrylcholinesterase (BuChE) possibly of Schwann cell origin recovers more rapidly than does AChE. (5) The muscle shows fine structural changes involving Z band dissolution and the breakdown of sarcoplasmic reticulum within hours after esterase inactivation. (6) This myopathy reaches a peak at three days after esterase inactivation and is almost fully recovered by two weeks. (7) It can be eliminated if, at the time of esterase inactivation, the nerve is cut or the acetylcholine receptors at the endplate are inactivated by alpha-bungarotoxin. We suggest that the myopathy, seen after DFP, is mediated by Ca2+ fluxes due to prolonged action of acetylcholine (ACh) in the absence of esterases.

79 citations


Journal ArticleDOI
TL;DR: The native trimeric esterase is a mixture of numerous hybrids of at least three protein subunits with differing but closely related primary sequences, which indicates that genetic differences concerning the composition of liver esterases exist between individuals.
Abstract: Three different subunits of highly purified pig liver esterase (EC 3.1.1.1) can be separated by analytical dodecyl sulfate electrophoresis, though their relative mobilities are very similar. The same subunit bands are obtained with microsomes, in which the esterases have been labeled with the specific active-site-directed inhibitor bis(4-nitro-[14C]phenyl)phosphate. The heterogeneity of the native trimeric enzyme is much more complex, as is demonstrated by isoelectric focussing and polyacrylamide gel electrophoresis. Fractions of esterase which were partially separated by preparative isoelectric focussing show differences in their subunit composition, their amino acid analyses, their tryptic peptide maps, and their C-terminal amino acids. From these experiments various features of the differing esterase subunits can be deduced. Based on the chemical results and on various experiments which did not indicate any secondary modification of the protein side-chains, the molecular basis of the esterase heterogeneity is discussed. We conclude that the native trimeric esterase is a mixture of numerous hybrids of at least three protein subunits with differing but closely related primary sequences. A comparison of the relative specificity of various preparations of pig liver microsomes indicates that genetic differences concerning the composition of liver esterase exist between individuals.

73 citations


Journal ArticleDOI
TL;DR: This analysis shows that esterase 6 in adult males is highly concentrated in the anterior ejaculatory duct, and it is suggested that eserase 6 plays a role in male reproduction.

73 citations


Journal ArticleDOI
TL;DR: The protease from Russell's viper venom that activates Factor V was purified by gel filtration and ion exchange column chromatography on sulfopropyl (SP)-Sephadex C-50 and was not inhibited by bovine antithrombin III in the presence or absence of heparin.

60 citations


Journal ArticleDOI
TL;DR: Results indicate that intestinal esterase from humans differs characteristically from esterases in experimental animals, and appears to be characteristically quite different from hepatic esters.

58 citations


Journal ArticleDOI
TL;DR: In vitro studies confirmed that the peak of synthesis and/or release of JH esterase from the fat body of last instar larvae occurred 4 days after ecdysis, and showed that fat body from JH-treated larvae released much less enzyme than controls.

54 citations


Journal ArticleDOI
TL;DR: In the wheat root, peroxidases and esterases specific for a-naphthyl esters of acetate, propionate and butyrate are concentrated in cell walls, particularly the outer wall of epidermal cells undergoing extension, and ferulic acid and diferulate were shown to be constituents of wheat-root cell walls.
Abstract: In the wheat root, peroxidases and esterases specific for a-naphthyl esters of acetate, propionate and butyrate are concentrated in cell walls, particularly the outer wall of epidermal cells undergoing extension. In contrast esterases specific for β-naphthyl esters of propionate and butyrate were intra- cellular and concentrated in epidermal and outer root-cap cells of the wheat root. Both α-naphthyl and β-naphthyl esters of longer-chain fatty acids proved to be poor substrates. The esterases and peroxidases associated with the outer epidermal wall may well be involved in turnover of phenolic acids cross-linked to polysaccharides. In this regard, ferulic acid and diferulate were shown to be constituents of wheat-root cell walls. The distribution of these substances can also be inferred from autofluorescence. Treatment with a commercial pig-liver esterase was without effect on the auto- fluorescence of the root cell-walls. Culture filtrates from Gaeumannomyces graminis did remove significant amounts of autofluorescent wall material. These preparations contained α-naphthyl acetate esterase as well as many polysaccharide hydrolase activities.

Journal ArticleDOI
TL;DR: A new esterase activity which hydrolyzes palmitoyl-CoA was found in the membrane fraction of Pseudomonas aeruginosa and seems to have specificity for long chain acyl esters with hydrophilic groups, whether thio- or oxy-ester.
Abstract: A new esterase activity which hydrolyzes palmitoyl-CoA was found in the membrane fraction of Pseudomonas aeruginosa. All the 11 strains of P. aeruginosa tested possessed this esterase activity. The esterase was constitutive and was fully active on the intact cell bodies toward substrates in the medium. It was located on the outer membrane of the cell envelope, and was not released into the culture medium. This activity was designated as OM (outer membrane) esterase. OM esterase was solubilized from the cell envelope with EDTA-Triton X-100 and purified 690-fold. It was a minor component of the outer membrane. Its molecular weight was approximately 55,000. The activity was rather stable to heat, a wide range of pH, and treatment with detergents and organic solvents. No cofactors were required. The pH optimum of the reaction was 8.5. Among various acyl-CoAs, only long chain (C12--C18) thioesters were hydrolyzed. OM esterase also hydrolyzed some kinds of oxy-esters such as p-nitrophenyl acyl esters, monoacyl esters of sucrose and Tween 80 (polyoxyethylene sorbitan monooleate). On the other hand, triglycerides, phospholipids, or hydrophobic monoesters were not hydrolyzed at all. Thus, this enzyme seems to have specificity for long chain acyl esters with hydrophilic groups, whether thio- or oxy-ester. Mutants deficient in this esterase activity were isolated. These mutants were unable to grow on Tween 80 as a sole carbon source. This suggests a possible role of OM esterase in the utilization of acyl esters as carbon sources.


Journal ArticleDOI
TL;DR: Glucoamylase, peroxidase, glucose oxidase, and carboxypeptidase Y were covalently bound to water-insoluble supports through their carbohydrates side chains through their carbohydrate side chains and showed very good operational stability.

Journal ArticleDOI
TL;DR: The purified pollen cutinase showed preference for primary alcohol esters, but it did not catalyze hydrolysis of tripalmitoyl or trioleyl glycerol at significant rates, suggesting that the pollen enzyme belongs to a new class of cutinases.

Journal ArticleDOI
TL;DR: It is concluded that kallikrein's active sites are facing the external environment of renal cortical cells in suspension with access to substrates, inhibitors, and antibody.

Journal ArticleDOI
TL;DR: Twelve acid hydrolases, 4 near-neutral hydrolase, and alkaline phosphatase were demonstrated in 0.34 M sucrose homogenates of Trypanosoma cruzi strain Y, with optimum pH at approximately 6.0 and maximum activity at pH 7.0.
Abstract: Twelve acid hydrolases, 4 near-neutral hydrolases, and alkaline phosphatase were demonstrated in 0.34 M sucrose homogenates of Trypanosoma cruzi strain Y: p-nitrophenylphosphatase and alpha-naphthylphosphatase, with optimum pH at approximately 6.0; alpha=ga;actpsodase. beta=ga;actpsodase. beta=g;icpsodase, N-acetyl-beta-glucosaminidase, cathepsin A and peptidase I and III, with optimum pH between 5.0 and 6.0; and arylsulfatase, cathepsin D, alpha-arabinase and alpha-mannosidase with optimum pH at approximately 4.0. alpha-Glucosidase, glucose-6-phosphatase and peptidase II had optimum pH at approximately 7.0. beta-Glycerophosphatase had a broad pH-activity curve from 4,0 to 7.4, with maximum activity at pH 7.0. The main kinetic characteristics of these enzymes and their quantitative assay methods were studied. No activity was detected for alpha-fucosidase, beta-xylosidase, beta-glucuronidase, elaidate esterase, acid lipase, and alkaline phosphodiesterase.

Journal ArticleDOI
TL;DR: The extracellular proteinase produced by a depressed strain of Serratia marcescens ATCC 25419 was purified and characterized and is devoid of esterase activity.

Journal ArticleDOI
TL;DR: Using isoelectric focussing and dodecyl sulfate electrophoretic methods, the various esterase isoenzymes appeared to have very similar, if not identical turnover rates; this method for the estimation of the turnover characteristics was applied to evaluate hormone effects on liver esterases.
Abstract: The irreversible reaction between liver esterases and the active-site-directed inhibitor bis(4-nitrophenyl)phosphate can be used in vivo both for the estimation of the esterase contents and for the measurement of the esterase degradation rates. A method based on this reaction is described which allows the simultaneous estimation of the rate constants of degradation and synthesis of esterases during a period of change in protein concentration. Rat liver was found to contain about 1 mg of organophosphate-binding esterases per g of fresh tissue while the microsomal fraction contains about 30 mg of esterases per g of microsomal protein. Esterase degradation and de novo synthesis were shown to remain in equilibrium for a period of at least five days following the injection of 10 mg bis(4-nitro-[14C]phenyl)phosphate per kg. The decrease of the relative amount of labeled esterases with time was found to follow first-order kinetics yielding an average esterase degrading constant of 0.0165 h−1 which corresponds to a half-life of 42 h. These data were confirmed by an independent experiment using one of the standard procedures for the estimation of degradation rates: [14C]leucine was incorporated and one of the esterases was subsequently isolated by immunoprecipitation. Using isoelectric focussing and dodecyl sulfate electrophoretic methods, the various esterase isoenzymes appeared to have very similar, if not identical turnover rates. This method for the estimation of the turnover characteristics was applied to evaluate hormone effects on liver esterases. The time course of the contents and the turnover of liver esterases was measured under the influence of glucagon treatment in diabetic rats and under the influence of high doses of insulin. The esterase content decreased faster than the average content of microsomal protein under the influence of glucagon. The reverse effect was observed with insulin-treated rats. Both insulin and glucagon apparently reduced the intracellular esterase turnover in rat liver. Kinetic analysis of the results revealed that insulin mainly lowered the esterase degradation rate, though the rate of esterase synthesis might also have been restricted. In the glucagon-treated rats the de novo synthesis of esterases was strongly reduced.

Journal ArticleDOI
TL;DR: Biochemical properties of esterase 6 in Drosophila melanogaster were investigated using partially purified preparations from three genotypes, and the differences demonstrated between allozymes would allow considerable scope, under appropriate conditions, for differential selection to operate between genotypes.
Abstract: Biochemical properties of esterase 6 in Drosophila melanogaster were investigated using partially purified preparations from three genotypes, 1/1, 1/2, and 2/2. The molecular weight of the enzyme is estimated to be about 90,000, and treatment with sodium dodecylsulfate cleaves the enzyme into four units with a molecular weight of about 22,000. The activity toward 28 naturally occurring esters was assayed and shown to vary considerably with substrate, the 1/1 preparation having in general higher activity than 1/2 and 2/2, which were very similar. Heat sensitivity, the effect of metal ions, and the effects of the presence or absence of an end product were also studied. The differences demonstrated between allozymes would allow considerable scope, under appropriate conditions, for differential selection to operate between genotypes.

Journal ArticleDOI
TL;DR: A locus has been found, an allele of which causes a modification of some allozymes of the enzyme esterase 6 in Drosophila melanogaster, but the mobility differences found are not large enough to conclude that ester enzyme 6 is sialylated.
Abstract: A locus has been found, an allele of which causes a modification of some allozymes of the enzyme esterase 6 in Drosophila melanogaster. There are two alleles of this locus, one of which is dominant to the other and results in increased electrophoretic mobility of affected allozymes. The locus responsible has been mapped to 3-56.7 on the standard genetic map (Est-6 is at 3-36.8). Of 13 other enzyme systems analyzed, only leucine aminopeptidase is affected by the modifier locus. Neuraminidase incubations of homogenates altered the electrophoretic mobility of esterase 6 allozymes, but the mobility differences found are not large enough to conclude that esterase 6 is sialylated.

Journal ArticleDOI
01 Jan 1979-Toxicon
TL;DR: Fractions 3, 4, 5, 6, 8 and 9 of the prep-disc electrophoretic separation of Loxosceles reclusa spider venom showed enzymic activity toward the hydrolysis of indoxyl-acetate and were therefore considered as hydrolytic enzyme components in the spider venom.

Journal ArticleDOI
TL;DR: The results obtained from inhibition studies by various enzyme-modifying reagents suggest the possible role of cysteine and histidine residues in the active site of both the enzymes.

Journal ArticleDOI
TL;DR: The purified esterase from human intestinal mucosa was found to be one of the carboxylesterases and hydrolyzed ester-type drugs, i.e., aspirin, clofibrate, indanyl carbenicillin and procaine, but did not hydrolyze amide- type drugs and choline-type Drugs.

Journal ArticleDOI
TL;DR: The results show that hormone-sensitive cholesterol esterase of adipose tissue has ready access to the neutral lipid core of plasma lipoproteins, either because the enzyme penetrates the polar shell or because the cholesterol esters in the core is exposed, at least intermittently, to allow enzyme-substrate complex formation.

Journal ArticleDOI
TL;DR: It is concluded that the retinyl ester lipoprotein complex possesses the additional physiological function of hydrolyzing its own retinyl Ester complement to unesterified retinol which may then combine with serum Retinol-binding protein.

Journal ArticleDOI
TL;DR: From the comparisons of the dissociation constants obtained from this kinetic method with the literature binding constants from the conventional static methods, it was suggested that the esterase active site differed from theventional binding sites on HSA.
Abstract: The inhibition of esterase activity of human serum albumin (HSA) by the presence of several drugs (IN) was kinetically studied assuming a scheme of competitive binding to HSA between substrate, p-nitrophenyl acetate (NPA), and IN. The IN included N-arylanthranilic acids, coumarin derivatives and prostaglandins. The conditions of excessive concentrations of HSA and IN compared with NPA were employed to avoid complexities due to multiple active sites of HSA. For the solubilization of IN some organic solvents were added and the effects of the solvents on the reaction parameters of NPA with HSA were investigated. The dissociation constants of IN-HSA complexes were determined from the double reciprocal plots based on the scheme. The bulkiness of the substituents on phenyl groups of N-arylanthranilic acids enhanced the inhibition. Warfarin did not inhibit the reaction at all. Prostaglandins showed rather little inhibitions. From the comparisons of the dissociation constants obtained from this kinetic method with the literature binding constants from the conventional static methods, it was suggested that the esterase active site differed from the conventional binding sites on HSA.

Journal ArticleDOI
TL;DR: The results indicate that human red cells contain at least four separate glutathione thiol esterases, one of which apparently occurs in multiple forms.

Journal ArticleDOI
TL;DR: The species relationship based on percentage homology of protein and esterase bands revealed that B. nigra and B. campestris are the parental species of B. carinata and not B. oleracea, as suggested on the basis of cytological studies.
Abstract: A considerable amount of variation with respect to soluble proteins and esterase isoenzyme pattern was observed between different species of Brassica. Naturally occurring amphidiploids had comparable proteins and isoenzyme patterns to either one or both of the parental species. The species relationship based on percentage homology of protein and esterase bands revealed that B. nigra and B. campestris are the parental species of B. carinata and not B. nigra and B. oleracea, as suggested on the basis of cytological studies. Elimination of a pair of chromosomes might have resulted into 2n=34 in the case of B. carinata. Further studies are needed to confirm this view. The peroxidase and catalase isoenzyme patterns did not show much variation in different species and amphidiploids.

Journal ArticleDOI
TL;DR: Proteins are present, and the parental protein patterns following electrophoresis are additive in the interspecific hybrid, and Esterase and malate dehydrogenase isozymes were detectable.
Abstract: Fremontia nectar contains glucose and fructose as major sugars. Two isoflavonoids, 5,7-dimethoxygenistein and its 4'-glucoside, occur in the nectar and cause it to fluoresce bright blue. No free amino acids were identifiable, but proteins are present, and the parental protein patterns following electrophoresis are additive in the interspecific hybrid. Esterase and malate dehydrogenase isozymes were detectable.