Showing papers on "Esterase published in 1978"
TL;DR: The isolation and characterization of valilactone is reported on, which is a new inhibitor from the strain MG147CF2 that has no effect on immune responses.
Abstract: brane, had important effects on cellular functions1^. These inhibitors included esterastin which inhibited esterase and suppressed immune responses45 (as well as) ebelactones which inhibited esterase but enhanced immuneresponses55. Continued screening for esterase inhibitors has resulted in the discovery of another inhibitor which we have named valilactone. Valilactone has no effect on immune responses. In this paper, we report on the isolation and characterization of valilactone. In the screening study, culture filtrates of many strains of various species of soil actinomycetes showed the activity to inhibit esterase. Wehave isolated a new inhibitor from the strain MG147CF2. This strain, closely related to Strepto-
144 citations
TL;DR: The esterase patterns of insecticide-resistant and susceptible strains of Culex pipiens fatigans Wiedemann, CuleX pipiens pipiens L., C. tarsalis Coquillett, and Anopheles albimanus WiedEMann, were investigated by starch gel electrophoresis and interspecific and interstrain differences in ester enzyme patterns and their relationship to resistance are discussed.
Abstract: The esterase patterns of insecticide-resistant and susceptible strains of Culex pipiens fatigans Wiedemann, Culex pipiens pipiens L., C. tarsalis Coquillett, and Anopheles albimanus Wiedemann, were investigated by starch gel electrophoresis. At least one highly active esterase is present in every organophosphate-resistant Strain of Culex spp. A highly active esterase B2, catalyzing the hydrolysis of β-naphthylacetate and being suppressible by DEF® ( S,S,S -tributyl phosphorotrithioate) is most probably associated with organophosphorus multiresistance in C. p. fatigans from California, Esterase B2 has no equivalent in chlorpyrifos-resistant C. p. pipiens from France. Interspecific and interstrain differences in esterase patterns and their relationship to resistance are discussed.
104 citations
TL;DR: The results suggest the presence of histochemically demonstrable nonspecific esterase activity predominantly in resting, mature T lymphocytes.
78 citations
TL;DR: In vivo studies of house fly adults treated with 3 H-labeled juvenile hormone I reveal a pattern of metabolism similar to that seen during NADPH-supplemented in vitro metabolism, and comparison of in vitro enzyme levels of the house fly, flesh fly, and blow fly showed that, although the enzymes were present in the latter two species, their activity on a per insect basis was considerably less than that of theHouse fly.
62 citations
Journal Article•
62 citations
TL;DR: It follow from these results that the C-4 acetyl residue is hydrolyzed by the microsomal carboxyesterase and substituents at C-3 and C-8 contribute to the selective enzymatic hydrolysis of theC-4acetyl residue of trichothecenes.
Abstract: The substrate specificity of microsomal nonspecific carboxyesterase [EC 3.1.1.1] from rabbit and rat livers was studied in vitro by using seven (A)-type and six (B)-type 12,13-epoxytrichothecene mycotoxins. The C-4 acetyl residues of diacetoxyscirpenol, T-2 toxin, monoacetylnivalenol (fusarenon-X), and diacetylnivalenol were selectively hydrolyzed by the microsomal esterase to yield the corresponding C-4-deacetylated metabolites: monoacetoxyscirpenol, HT-2 toxin, nivalenol, and 15-acetylnivalenol, respectively. The C-3 acetyl group of monoacetyldeoxynivalenol and the C-8 acetyl group of tetraacetoxyscirpen were also deacetylated. Triacetoxyscirpen gave rise to two unidentified metabolites, which may include a C-4-deacetylated product. 8-Hydroxydiacetoxyscirpenol (neosolaniol), HT-2 toxin, acetyl-T-2 toxin and tetraacetylnivalenol were unaffected by this type of hydrolysis. It follow from these results that the C-4 acetyl residue is hydrolyzed by the microsomal carboxyesterase and substituents at C-3 and C-8 contribute to the selective enzymatic hydrolysis of the C-4 acetyl residue of trichothecenes. Kinetic analysis showed that rabbit microsomal esterase possessed a high affinity for (A)-type trichothecenes such as T-2 toxin and diacetoxyscirpenol, and that of rat microsomes possessed a high affinity for (B)-type trichothecenes such as monoacetylnivalenol (fusarenon-X). The significance of this specific deacetylation reaction is discussed in relation to the biological activity of the trichothecene derivatives as revealed by their inhibitory effect on protein synthesis in rabbit reticulocytes.
57 citations
TL;DR: Both lipase and esterase activities were present in intestinal contents of all newborns studied, from the first day of life to the second, in contrast to adults given a test meal, where both activities decreased markedly in infants on feeding.
Abstract: Both lipase and esterase activities were present in intestinal contents of all newborns studied, from the first day of life. In adults given a test meal lipase activity increased and esterase activity remained unchanged. In contrast, both activities decreased markedly in infants on feeding. During the digestion of the test meal the lipase activity in intestinal contents of the infants was much lower than in adults (ratio of median values 1:27) and the esterase activity was also several fold lower (ratio of median values 1:1.3). Speculation Newborn infants often absorb lipids less efficiently than adults. One contributing factor may be that their incompletely developed pancreas responds to feedings with comparatively low outputs of lipolytic enzymes. The newborn may be more dependent than adults on auxiliary sources of lipase activity such as the pharyngeal lipase and/or the bile-stimulated lipase in human milk.
56 citations
49 citations
TL;DR: Ion-exchange chromatography and Sephadex gel filtration were used to isolate a soluble proteolytic enzyme from culture forms of Trypanosoma cruzi, concluding that the enzyme possesses active sulfhydryl groups.
46 citations
TL;DR: The formula C28H46N2O6 was established for 1 by high-resolution mass spectroscopy and elemental analysis and a colorless tetrahydroesterastin was determined to be a ƒÐ-lactone of a member of mycolic acids.
Abstract: Esterastin (1) is obtained as a colorless powder, mip 99-100•Ž; [ƒ¿]23D+1l•‹ (c 1, CHCI3); UV 265 nm (sh) in 95 % aqueous methanol; IR (KBr) 1840 (ƒÀ-lactone), 1730, 1185 (ester), 1645, 1610 and 1545 (amide) cm-1; positive RYDON-SMITH and anisaldehyde-H2SO4 reactions and negative ninhydrin reaction.1) The formula C28H46N2O6 was established for 1 by high-resolution mass spectroscopy and elemental analysis. The 1H NMR spectrum of 1 in CDCI3 showed two Cmethyl groups (ƒÐ 0.90, t), an N-acetyl group (ƒÐ 2.03, s) and four olefinic protons (ƒÐ 5.4•` 5.7, m) as shown in Table 1. Catalytic hydrogenation of 1 in methanol with PtO2 at room temperature for 2 hours in a Parr apparatus gave a colorless tetrahydroesterastin (2), mp 102.5-104•Ž; m/e 511, (M+ 1)+; UV 260 nm (sh) in 95% aqueous methanol; IR (KBr) 1830 (ƒÀ-lactone), 1720, 1185 (ester), 1650, 1610 and 1545 (amide) cm -1. Alkaline hydrolysis of 1 (498 mg, 0.98 mmole) with I N KOH (4 ml) in dioxane (250 ml) under gently refluxing for 4 hours afforded a colorless oil (175 mg) which was determined to be a ƒÐlactone (3) of a member of mycolic acids*, [ƒ¿]27D +21.5•‹(c 1, CHCI3); m/e 350.2785 (M+, calcd. for C22Hs8O3, m/e 350.2818); IR (KBr) 1700 and 1 175 (ƒÐ-lactone) cm-1 '. Catalytic hydrogenation of the ƒÐ-lactone (3) gave a colorless tetrahydro derivative (4), mp 107.5•Ž; m/e 355, (M+1)+. Acetylation of 3 and 4 with acetic anhydride in
38 citations
Journal Article•
TL;DR: A standard procedure for staining alpha naphthyl acetate and chloroacetate esterase activities was modified by extending the range of pH of the incubation mixture and the duration of staining and was applied to cat, dog, goat, guinea pig, hamster, human, pig, rabbit, rat, and sheep leukocytes.
Abstract: Cytochemical methods for alpha naphthyl acetate esterase and chloroacetate esterase have been used to identify human monocytes and granulocytes. In this study, a standard procedure for staining alpha naphthyl acetate and chloroacetate esterase activities was modified by extending the range of pH of the incubation mixture and the duration of staining and was applied to cat, dog, goat, guinea pig, hamster, human, pig, rabbit, rat, and sheep leukocytes. The results for both enzymes showed (1) incubation time and pH had discrete effects on staining and (2) species differences for in vitro conditions to demonstrate esterase activity were pronounced.
TL;DR: The purpose of this investigation was to ascertain the lipolytic activities (specifically, esterase) of those species of Candida that are most commonly isolated from human infections.
Abstract: The purpose of this investigation was to ascertain the lipolytic activities (specifically, esterase) of those species of Candida that are most commonly isolated from human infections. Eight species of Candida were surveyed for their ability to hydrolyze various polyoxyethylene sorbitan compounds (Tweens). Of the 64 isolates tested, each had activity for at least one of the substrates. Most of the isolates hydrolyzed Tweens 40, 60, and 85. In contrast, none hydrolyzed Tween 80. Only one species hydrolyzed Tween 20. The patterns of precipitation resulting from reactions of fatty acids hydrolyzed from Tweens 40, 60, and 85 with calcium ions in the media were also useful in distinguishing some of the species. In the past, such reactions have been reported as being dependent on esterase activity.
TL;DR: PKK was activated with Cephotest and dextran sulphate under various conditions and the resulting kallikrein (KK) assayed on a chromogenic peptide substrate for this enzyme showed progressive inhibition of plasma KK at 37°C showing that in normal plasma some KK is immediately bound by α2-macroglobulin and C1-esterase inhibitor even when activation takes place at 0°C.
TL;DR: Light- and heavy-plasma membrane fractions have been isolated from rabbit neutrophils and a chymotrypsin-like esterase has been shown to be present in these fractions, and binding by subcellular fractions shows that the highest specific binding was observed in the light- plasma membrane.
TL;DR: Arguments are presented for the existence of distinct ester- and aldehyde-binding sites and NAD+ and NADH stimulated the steady-state rate of ester hydrolysis at concentrations expected on the basis of their Michaelis constants from the dehydrogenase reaction.
Abstract: The hydrolysis of 4-nitrophenyl acetate catalysed by cytoplasmic aldehyde dehydrogenase (EC 1.2.1.3) from sheep liver was studied by steady-state and transient kinetic techniques. NAD+ and NADH stimulated the steady-state rate of ester hydrolysis at concentrations expected on the basis of their Michaelis constants from the dehydrogenase reaction. At higher concentrations of the coenzymes, both NAD+ and NADH inhibited the reaction competitively with respect to 4-nitrophenyl acetate, with inhibition constants of 104 and 197 micron respectively. Propionaldehyde and chloral hydrate are competitive inhibitors of the esterase reaction. A burst in the production of 4-nitrophenoxide ion was observed, with a rate constant of 12 +/- 2s-1 and a burst amplitude that was 30% of that expected on the basis of the known NADH-binding site concentration. The rate-limiting step for the esterase reaction occurs after the formation of 4-nitrophenoxide ion. Arguments are presented for the existence of distinct ester- and aldehyde-binding sites.
TL;DR: A carboxylesterase from wild oat (Avena fatua L.) which hydrolyses benzoylprop ethyl [ethyl N-benzoyl-N-(3,4-dichlrophenyl)-2-aminopropionate] to thc herbicidally active bnzoyl prop acid, was partially purified by (NH4)2 SO4 fractionation and Sephadex G-100 gel filtration A 8.3-fold purification was obtained with 46% recovery as discussed by the authors.
Abstract: Summary: Resume: Zusammenfassung
A carboxylesterasc from wild oat (Avena fatua L.) which hydrolyses benzoylprop ethyl [ethyl N-benzoyl-N-(3,4-dichlrophenyl)-2-aminopropionate] to thc herbicidally active bnzoylprop acid, was partially purified by (NH4)2 SO4 fractionation and Sephadex G-100 gel filtration A 8.3-fold purification was obtained with 46% recovery. The rate of de-esterification of 14C-benzoylprop ethyl was 0.1 ηmoles/16 h at standard assay condition of 1 mg lyophilized enzyme preparation in 0.1 ml phosphate buffer (0.1 M. pH 7.0). substrate 5ηM The wild oat esterase was stable and activity as a function of reaction time. enzyme and substrate concentration was charaterized Incubation with a-chymotrypsin reduced wild oat esterase activity as did the presence of ethanol in reaction mixtures Esterase actvity for14C-benzoylprop ethyl was not detected in preparations from wheat (Triticum aestlivum L.). Evidence was obtained which suggested the presence of an inhibitor in wheat.
Hydrolyse de l'herbicide benzoylprop ethyle par l'esterase de la folte-avoine
Une carboxylesterase de la folle-avoine (Avena fatua L.) qui hydrolyse Ie benzoylprop ethyle (N-benzoyl-N-(3.4-dichlorophenyle)-2-aminopropionate d'ethyle) en acidc benzoyprop, actif sur les mauvaises herbes, a ete partiellement purifiee par fractionnement au moyen de (NH4)2 SO4 et filtration sur gel Sephadex G-100 Une purification de 8.3 folis a eteobtenue avec 46% de recuperation Le taux de de-esterification du 14C-benzoylprop ethyle a ete de 0.1 ηmole en 16 h aux conditions standard d'essai: 1 mg de preparation d'enzyme lyophilise dans 0,1 ml de tampon au phosphate (0, 1 M pH 7,0) pour 5ηM de substrat L'esterase de LA folle-avoine a ete stable et il a pu etre monlre que son activiteetait fonction de la duree de reaction ainsi que de la concentration de l'enzyme et du substrat. L'incu-bation avec de l'o-chymotrypsine a reduit L'activite de l'esterase de la folle-avoine de meme que la presence de l'ethanol dans les melanges en reaction. ll n'a pas ete decele dans des preparations dc ble (Triticum sativum) d'activite d'une esterase pour le 14C-benzoylprop-ethyle. Certainsfaitls ont ete observer qui sug-gerent la presence d'un inhibiteur dans le ble
Hydrolyse des Herbizids Benzoylprop-athyl dunh Flughafer- esterase
Es wurde eine Carboxylesterase von Flughafer (Avena fatua L.), die Benzoylprop-athyl [Athyl N-benzoyl-N-(3,4)-dichlor- phenyl)-2 aminopropionat] zur herbizidwirksamen Benzoyl- prop-Saure hydrolysiert. dureh (NH4)2 SO4 -fraktionierung und Gelfiltration an Sephadex G-100 teilweise gereinigt Dabei wurde eine 8,3-fache Reinigung bei einer Wiederfmdungiirate von 46% erzielt. Die Hydrolyserate von 14C-Benzoylprop-athyl betrug 0.1 ηmol/16 h unter Standurdbedingungen von 1 mg lyophilisienetn Enzympraparat in 0.1 ml Phosphatpuffer (0.1 M, pH 7.0) und 5 ηm Substrat Die flughaferesterase war stabil und die Enzymaktiviat war von der Reaktionszeit abhangig. Das Enzym und die Substratkonzentration wurden beschrieben. Inkubation mit α-Chymotrypsin verringerte die Esteraseaktivitat. DurcH die Gegenwart von Athanol in den Reaktionsgemlschen wurde die Aktivitat ebenfalls reduziert. In Weizenpraparationen (Triticum aestivum L.) konnte keine Esteraseaktivitat fur 14C-Benzoylprop-athyl festgestellt werden. Es gab Hinweise dafur, dass in Weizen ein Hemmstoff vorkommt.
TL;DR: Fluorigenic substrates prepared from 4-methylumbelliferone provide a simple, convenient method for detecting and assaying group-specific hydrolase activity in small quantities of whole mycobacteria, especially slowly growing strains in which biochemical properties are very difficult to detect by other techniques.
Abstract: Fluorigenic substrates prepared from 4-methylumbelliferone provide a simple, convenient method for detecting and assaying group-specific hydrolase activity in small quantities of whole mycobacteria. Physico-chemical properties of the enzymes such as pH dependence and heat stability may also be studied. A technique is described for studying glycosidase, hexosaminidase, acid phosphatase, and acyl esterase activity in seven mycobacterial species. Such techniques will be a useful aid to the taxonomy, identification, and quantification of mycobacteria, especially slowly growing strains in which biochemical properties are very difficult to detect by other techniques.
TL;DR: The activity of esterase in baker's yeast cells and in cell fractions was estimated using 2-oxoglutaric acid diethyl ester, p-nitrophenyl acetate and α- and β-naphthyl acetates as substrates using an enzymic method and by indirect evidence.
Abstract: The activity of esterase in baker's yeast cells and in cell fractions was estimated using 2-oxoglutaric acid diethyl ester, p-nitrophenyl acetate and α- and β-naphthyl acetate as substrates.
The esterase hydrolysing 2-oxoglutaric acid ester was shown to be located inside the cell, both directly by an enzymic method and by indirect evidence. The activities of the esterases hydrolysing aryl esters were found to vary greatly with the different substrates and estimation methods used. The presence of esterase activity towards phenyl and naphthyl esters in both cell wall digests and sphaeroplast lysates confirms the localization of at least one esterase in both sides of the plasma membrane barrier. Depending on the method of evaluation, values between 80 and 40% of the total were obtained for the proportion of esterase activity located outside the plasma membrane, the most reliable values being about 50–65%.
TL;DR: The content of choline esters in the haemolymphs and smooth muscles was quantitatively determined by means of gas chromatography and the realization of the “catch” mechanism was discussed.
TL;DR: A unique example of the influence of protein structure on the reactivity of functional amino acid residues is described and an important aspect of chemical modification of enzymes is illustrated.
Abstract: Coupling of bovine carboxypeptidase A with diazotized 5-amino-1H-tetrazole increases esterase activity, decreases peptidase activity slightly, and modifies one tyrosyl residue. Subsequent nitration of the azoenzyme has no further effect on esterase activity, decreases peptidase activity markedly, and modifies a second tyrosyl residue. Analysis of the azopeptides isolated from a chymotrypsin digest of the doubly modified enzyme by affinity, ion exchange, and high pressure liquid chromatography indicates that the principal residue modified by diazo-1H-tetrazole is Tyr-248. Analysis of the nitropeptides isolated by similar procedures indicates that nitration occurs mainly at Tyr-198. This residue becomes susceptible to modification only as a consequence of a conformational change that accompanies azo coupling of Tyr-248. These results describe a unique example of the influence of protein structure on the reactivity of functional amino acid residues and illustrate an important aspect of chemical modification of enzymes.
TL;DR: In this paper, a wide variety of simple esters were tested for the ability to protect LIF against inactivation by the serine esterase inhibitor phenylmethylsulfonyl fluoride (PMSF).
Abstract: Previously reported experiments suggested that an esterase or a protease, or both, might participate in the expression of human leukocyte migration inhibitory factor (LIF). To clarify this further, a wide variety of simple esters were tested for the ability to protect LIF against inactivation by the serine esterase inhibitor phenylmethylsulfonyl fluoride (PMSF). α-N-benzoyl-L-arginine ethylester (BAEE), a typical trypsin substrate, and bis-p-nitrophenyl phosphate (BNPP); a phosphodiester, were the only esters capable of retaining LIF activity in the presence of PMSF. Agents chemically closely related to these esters were inactive. Moreover, the protection afforded by BAEE and BNPP was the kind that would be anticipated if the esters and irreversible inhibitor competed for the same site on LIF. BAEE and BNPP also protected against inactivation by di-isopropyl-fluorophosphate (DFP), another irreversible serine esterase inhibitor. In addition, LIF-treated leukocytes partly escaped migration inhibition in the presence of BAEE and BNPP, respectively. These results indicate that human LIF contains a serine residue necessary for lymphokine activity. It is still not proved, however, that LIF as an enzyme is capable of hydrolyzing BAEE and BNPP, although it seems highly possible. The substrate specificities of a putative LIF enzyme are discussed on the basis of the chemical structure of BAEE and BNPP.
TL;DR: The non-specific carboxyl (serine) esterase of the human pulmonary alveolar macrophage was localized ultrastructurally using α-naphthyl acetate and hexazotized pararosanilin to form an ectoenzyme which may function as mediator of cell response to injurious agents from the outside.
Abstract: The non-specific carboxyl (serine) esterase of the human pulmonary alveolar macrophage was localized ultrastructurally using alpha-naphthyl acetate and hexazotized pararosanilin. The reaction product principally outlined the outer side of the plasma membrane. Consequently, this esterase is an ectoenzyme which may function as mediator of cell response to injurious agents from the outside.
Journal Article•
TL;DR: Methodological studies using different fixatives indicate that apparent similarity of esterase reaction at different sites may camouflage an underlying difference in the nature of the esterases at these sites.
Abstract: As a base line for future cell genetical studies the authors record the distribution of non-specific esterase reaction in the various histologically distinguishable cell types of the mouse epididymis. The findings are correlated with previous descriptions of the lobar structure of the organ. Assuming the sequence of lobes of the head to be as implied in these classical descriptions, the esterase activity of the epithelial cells gradates between strong to weak several times along the length of the epididymal duct. The relationship of the lobes to each other, as seen in transverse sections, is described. Methodological studies using different fixatives indicate that apparent similarity of esterase reaction at different sites may camouflage an underlying difference in the nature of the esterases at these sites.
TL;DR: A new esterase locus (Es-13) has been identified in Mus musculus and was mapped on Chr 9 by recombinant inbred lines and by conventional backcrossing experiments.
Abstract: A new esterase locus (Es-13) has been identified in Mus musculus. Strains AEJ/GnRk, LG/J, SJL/J, and SWR/J carry a recessive allele, Es-13
b, for a locus possibly involved in the posttranslational modification of a kidney esterase. All other strains observed carried the dominant Es-13
a allele. Es-13 was mapped on Chr 9 by recombinant inbred lines and by conventional backcrossing experiments. Backcross data produced the following gene order and map distances: Lap-1 (31.6±7.5 cM) Es-13 (2.6±2.6 cM) Mod-1.
TL;DR: The esterase-9A is the first testosterone-dependent isozyme of the mouse carboxylesterase (carboxylicester hydrolase, EC 3.1.1) system which has been isolated.
TL;DR: Three genetic markers - group-specific component (Gc), alpha1-antitrypsin, and esterase D - were examined in a population of Eskimos from Igloolik in the eastern Canadian Arctic and found to be polymorphic.
Abstract: Three genetic markers – group-specific component (Gc), α1-antitrypsin, and esterase D – were examined in a population of Eskimos from Igloohk in the eastern Canadian Arctic. Gc and esterase
TL;DR: The results emphasize the importance of controlling and manipulating growth conditions for the assessment of inter- and intraspecies variations in the isozymes of Paramecium.
Abstract: SYNOPSIS Enhanced esterase C activity could be demonstrated by starch gel electrophoresis in various stocks of Paramecium spp. (P. primaurelia stocks 90 and 540, P. biaurelia stock 93, P. tetraurelia stock 29. P. pentaurelia stock 87, P. octaurelia stocks 31 and 300, and P. multimicronucleatum species 3, stock 8 MO) grown in Adaptation Medium. This esterase, however, was barely detectable when they were cultivated in Axenic Medium. Addition of trypticase to Adaptation Medium resulted in reduction of esterase C in the ciliates. This effect is ascribable to Na acetate present in trypticase. Since esterase C increased with the decrease in acetate concentration (as estimated by gas-liquid chromatography) during growth of Paramecium, acetate appears to be utilized by the cells. Sensitivity of esterase C to acetate occurs in all 6 species of Paramecium examined. Different stocks within a species may have different levels of sensitivity; in one case this is genetically determined. The results emphasize the importance of controlling and manipulating growth conditions for the assessment of inter- and intraspecies variations in the isozymes of Paramecium.