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PubMed1999

Purification and characterization of an esterase involved in cellulose acetate degradation by Neisseria sicca SB.

An esterase catalyzing the hydrolysis of acetyl ester moieties in cellulose acetate was purified 1,110-fold to electrophoretic homogeneity from the culture supernatant of Neisseria sicca SB, which can assimilate cellulose acetate as the sole carbon and energy source. The purified enzyme was a monomeric protein with a molecular mass of 40 kDa and the isoelectric point was 5.3. The pH and temperature optima of the enzyme were 8.0-8.5 and 45 degrees C. The enzyme catalyzed the hydrolysis of acetyl saccharides, p-nitrophenyl esters of short-chain fatty acids, and was slightly active toward aliphatic and aromatic esters. The K(m) and Vmax for cellulose acetate (degree of substitution, 0.88) and p-nitrophenyl acetate were 0.0162% (716 microM as acetyl content in the polymer) and 36.0 microM, and 66.8 and 39.1 mumol/min/mg, respectively. The enzyme was strongly inhibited by phenylmethylsulfonyl fluoride and diisopropyl fluorophosphate, which indicated that the enzyme was a serine esterase.

Amino Acid Sequence↗

PubMed2001

DEF sensitive esterases in homogenates of larval and adult Helicoverpa zea, Spodoptera frugiperda, and Agrotis ipsilon (Lepidoptera: Noctuidae).

Homogenates of Helicoverpa zea (Boddie), Agrotis ipsilon (Hufnagle), and Spodoptera frugiperda (J. E. Smith) third instars and adults contained S,S,S-tri-n-butyl phosphorotrithioate (DEF)-sensitive enzymes that hydrolyzed trans-cypermethrin and two known esterase substrates, alpha-naphthyl acetate and beta-naphthyl acetate. Except for H. zea with alpha-naphthyl acetate, larval preparations were more active than those of adults, and no marked sex differences were apparent. The hydrolysis of trans-cypermethrin in noctuid preparations were inhibited by DEF, with pI50 values ranging from 4.5 to 6.7. DEF was a potent inhibitor of the degradation of general carboxylesterase substrates alpha-naphthyl acetate and beta-naphthyl acetate in some cases. Electrophoretic studies confirmed the presence in noctuid gut homogenates of one or more DEF-sensitive esterases that hydrolyzed alpha-naphthyl acetate and beta-naphthyl acetate and that were completely inhibited by dichtorvos.

Animals↗

PubMed2006

Role of kdr and esterase-mediated metabolism in pyrethroid-resistant populations of Haematobia irritans irritans (Diptera: Muscidae) in Brazil.

The horn fly, Haematobia irritans irritans (L.) (Diptera: Muscidae), has become a problem for Brazilian cattle producers even though its introduction into Brazil is relatively recent. Failure to control this cattle pest is becoming a concern, and horn fly populations from several ranches from the state of Mato Grosso do Sul were surveyed for pyrethroid resistance. Susceptibility bioassays revealed that cypermethrin resistance was widespread and reached high levels in horn fly populations throughout the state, with resistance factors (RFs) ranging from 50.4 to 704.8. Synergist bioassays failed to detect a major role for esterases as a pyrethroid resistance mechanism in these populations, except for the highly pyrethroid-resistant Estrela do Oeste population (RF = 704.8). The kdr sodium channel gene mutation was not detected in eight of the 13 populations, but < 7% of individuals from four populations and 50% of the flies from Estrela do Oeste exhibited this mutation. Neither the superkdr sodium channel gene mutation nor a resistance-associated gene mutation in the HialphaE7 carboxylesterase were found in any of the fly populations. Although target site insensitivity (kdr) and esterase-mediated metabolism occur in horn fly populations from Mato Grosso do Sul state, it seems that they are not the major mechanism causing pyrethroid resistance in most of these populations.

Animals↗

PubMed2001

Histochemical localization of esterases in the integument of the female Boophilus microplus (Acari: Ixodidae) tick.

The cattle tick Boophilus microplus (Canestrini) is one of the most important ectoparasites affecting tropical cattle with worldwide distribution. Application of organophosphate compounds (OP) is extensively used as a tick control method. However, the appearance of ticks resistant to the OP decreases the therapeutic efficacy of such compounds. Esterases have been implicated as potential biochemical mechanisms for detoxification in B. microplus larvae. We found increased esterase activity in the inner layers of the integument of OP resistant adult female B. microplus ticks as compared with the OP susceptible ticks. We discuss the potential role of these enzymes during acaricide metabolism and propose future research.

Animals↗

PubMed1985

Measurement of rat-intestinal cefuroxime axetil esterase activity: comparison of an h.p.l.c. and coupled-enzyme assay.

An alternative method to h.p.l.c. for determining cefuroxime axetil esterase (CAE) activity has been developed which involves coupling acetaldehyde, produced in the esterase reaction, with alcohol dehydrogenase (ADH) to provide a direct reading spectrophotometric assay. The optimum temperature and concn. of NADH, cefuroxime axetil and ADH for the assay are 37 degrees C, 160 microM, 2.9 mM and 160 U/ml, respectively. The coupled assay was more reproducible but less sensitive than the h.p.l.c. assay, and the two methods gave results that were not significantly different (P greater than 0.05). Both assays responded linearly when CAE activity was measured as a function of protein concn., however, the coupled assay was impaired at ionic strengths greater than 0.2 M NaCl, whereas no adverse effects were seen with the h.p.l.c. assay up to 0.5 M NaCl.

Alcohol Dehydrogenase↗

PubMed1995

Metabolic deactivation of the herbicide thiazopyr by animal liver esterases.

1. Thiazopyr was hydrolysed in vitro to its corresponding acid by rabbit and porcine liver esterases. 2. A wide range of thiazopyr esterase activity was observed in extracts from liver acetone powders from 15 animal species with bovine, rabbit and pigeon showing the highest activities. 3. Using soybean tissue culture cells and Arabidopsis seedlings, the acidic metabolite was shown to possess < 1% of the herbicidal activity of thiazopyr. 4. We propose that biotransformation of thiazopyr to the acid is a critical pathway of metabolism in animals and plants.

Animals↗

PubMed1981

Histochemical studies on genetical control of hormonal enzyme inducibility in the mouse. IV: Cellular localization of androgen sensitive nonspecific esterase in the epididymis.

Nonspecific esterase of mouse epididymis has previously been studied histochemically, using alpha naphthyl-acetate and 5-bromoindoxyl acetate techniques, as well as certain inhibitors. Epithelial cell types of the epididymis have been characterized, and certain esterase isozymes in a particular cell type, is shown to be androgen dependent. When mice of different strains were castrated or treated with antiandrogens, the characteristic histochemical reaction product disappeared or was greatly reduced. Androgen treatment of castrated animals caused the reaction in the cells concerned to return to normal. This method can now be applied to the study of epididymides of genetically sex-reversed chromosomal female, to analyze genetic control of X-chromosomal activation.

Androgens↗

PubMed1981

Rapid method for determining T lymphocyte levels using acid alpha-naphthyl acetate esterase.

A method for rapidly determining levels of T lymphocytes in humans is presented. The method involves staining lymphocytes in peripheral blood or buffy coat smears for acid alpha-naphthylacetate esterase for 1 hr at 37 C. After counterstaining with Wright's stain, the percentage of esterase-positive lymphocytes accurately reflects the percentage of lymphocytes forming E rosettes with sheep erythrocytes.

Carboxylic Ester Hydrolases↗

PubMed2003

Accumulation of short n-chain ethyl esters by esterases of lactic acid bacteria under conditions simulating ripening Parmesan cheese.

EstA from Lactobacillus helveticus CNRZ32 (Lbh-EstA), EstB, and EstC from Lactobacillus casei LILA, and EstA from Lactococcus lactis MG1363 (Lcl-EstA) were evaluated for their ability to accumulate esters in a model system simulating Parmesan cheese ripening conditions (10 degrees C, 2 to 3% NaCl, pH 5.4 to 5.5, aw = 0.850 to 0.925) using Capalase K from kid goat as a positive control. All of the LAB esterases and Capalase K mediated the accumulation of esters in the model system in an enzyme specific manner, which was influenced by a, and selectivity for fatty acid chain-length. In general, enzyme mediated accumulation of ethyl esters was higher at aw values of 0.850 and 0.900 than at aw of 0.925, demonstrating that aw is a critical parameter influencing ester accumulation. The substrate selectivity of esterases, aw, and enzyme type may be important factors in the development of fruity flavors, as evidenced by results in this model system simulating Parmesan cheese ripening conditions.

Butyrates↗

PubMed1977

Distribution of chloramphenicol acetyltransferase and chloramphenicol-3-acetate esterase among Streptomyces and Corynebacterium.

Chloramphenicol-3-acetate esterase activity was detected in cell-free extracts of strains of Streptomyces venezuela, Streptomyces sp. and Streptosporangium viridogriseum var. kofuense which produced chloramphenicol and also Corynebacterium hydrocarboclastus which produced chloramphenicol analogs (corynecins). None of the cell-free extracts of chloramphenicol- or corynecin-producing strains possessed chloramphenicol acetyltransferase activity under conditions which avoided the influenced of the esterase activity. Among 20 strains examined that did not produce chloramphenicol, chloramphenicol acetyltransferase was detected in cell-free extracts of one strain of Streptomyces coelicolor Müller and one strain of S. fradiae ISP5063.

Acetyltransferases↗

PubMed1995

Isolation, characterization and biological activities of novel triprenyl phenols as pancreatic cholesterol esterase inhibitors produced by Stachybotrys sp. F-1839.

Ten triprenyl phenol metabolites were isolated as inhibitors of pancreatic cholesterol esterase from cultures of Stachybotrys sp. F-1839 by solvent extraction and column chromatographies. Combination of spectroscopic analyses revealed that two of these compounds are K-76 (1) and stachybotrydial (2), and that the remaining eight are new congeners (designated F1839-A (3), -B (4), -C (5), -D (6), -E (7), -F (8), -I (9) and -J (10). These compounds inhibited pancreatic cholesterol esterase by 50% at 6 x 10(-5) to 1.1 x 10(-1) M. Inhibition of the enzyme by compound 2, the most potent one among these compounds, was time-dependent and irreversible. When administered to normal rats, 2, at a single oral dose of 100 mg/kg, reduced [14C]cholesterol absorption by 50-60%. In cholesterol-fed mice, dietary supplementation of 2 (0.1%) for 14 days resulted in a 20% reduction in serum total cholesterol level without causing significant change in the high density lipoprotein cholesterol level.

Animals↗

PubMed2000

Macrolide esterase-producing Escherichia coli clinically isolated in Japan.

Current Japanese clinical practice involves the usage of large amounts of new macrolides such as clarithromycin and roxithromycin for the treatment of diffuse panbronchiolitis, Helicobacter pylori and Mycobacterium avium complex infections. In this study, the phenotypes, genotypes, and macrolide resistance mechanisms of macrolide-inactivating Escherichia coli recovered in Japan from 1996 to 1997, were investigated. The isolation rate of erythromycin A highly-resistant E. coli (MIC > or = 1,600 microg/ml) in Japan slightly increased from 0.5% in 1986 to 1.2% in 1997. In six macrolide-resistant strains, recovered from the strains collected for this study during 1996 to 1997, the inactivation of macrolide could be detected with or without added ATP in the assay system. The appearance of erythromycin A-inactivating enzyme independent of ATP was novel from Japanese isolates, and the 1H NMR spectra of oleandomycin hydrolyzed by the three ATP-independent isolates were examined. It was clearly shown that the lactone ring at the position of C-13 was cleaved as 13-H signal in aglycon of oleandomycin upper shifted. These results suggested the first detection of macrolide-lactone ring-hydrolase from clinical isolates in Japan. These results suggested the first detection of an ATP-independent macrolide-hydrolyzing enzyme from Japanese clinical isolates. Substrate specificity of the macrolide-hydrolyzing enzyme was determined with twelve macrolides including the newer members of this group and it was found that not only erythromycin A but also the new macrolides, such as clarithromycin, roxithromycin, and azithromycin were inactivated. The NMR data, broad spectrum of activity, and independence of co-enzyme supported our naming of the enzyme as a macrolide esterase. PCR methodology was employed to detect an ereB-like gene from the 3 isolates producing macrolide esterase, and one of these was subsequently shown to contain both ereB-like and ermB-like genes. It was also clearly shown that the other three isolates, which inactivated macrolide in the presence of ATP, had an mphA-like gene.

Anti-Bacterial Agents↗

PubMed1974

Isolation and characterization of an esterase-active enzyme from pronase with special reference to activation of Clostridium botulinum type E progenitor toxin.

(1) By sequential chromatography on CM-Sephadex, SP-Sephadex and Sephadex G-100, an esterase-active enzyme was isolated from a commercial preparation of pronase, (2) The purity of the isolated enzyme was proven by disc electrophoresis and sedimentation analysis. (3) The molecular weight of the esterase-active enzyme was approximately 16,000. The sedimentation coefficient was 1.85 S. The N- and C-terminal amino acids were asparagine and valine, respectively. (4) The enzyme was similar to that of bovine trypsin in the substrate specificity. It appeared to be the same as the trypsin-like enzyme isolated from pronase by Wähyby (1968). However, the relative rates of hydrolyses of different substrates by the enzyme differed from those of bovine trypsin. (5) The enzyme activated Clostridium botulinum type E progenitor toxin. Even a higher toxicity was resulted by treating the progenitor toxin with this enzyme than with bovine trypsin. (6) The results support the hypothesis that activation of type E progenitor toxin involves hydrolysis of a lysine ester bond.

Amino Acids↗

PubMed1978

[Species specific esterase profiles in the genus Serratia].

Esterases of 62 Serratia marcescens, S. liquefaciens, S. plymuthica and S. marinorubra strains were analysed by electrophoresis in polyacrylamide-agarose gel. The comparative distribution of bands showed that the four Serratia species were characterized by distinct electrophoretic patterns of their esterases.

Esterases↗

PubMed1976

Genetic variation in two natural populations of Biomphalaria tenagophila: esterases and alcohol dehydrogenase.

The polymorphism of two natural populations of snails, Biomphalaria tenagophila, from São José dos Campos, São Paulo State (SJ) and from Núcleo Bandeirante, Distrito Federal (BN), was studied with respect to esterase and alcohol dehydrogenase (ADH) zymograms. The two population zymograms do not differ qualitatively. However the high frequency of esterase a and b bands in SJ and of e,f and h in NB, is a diagnostic mark. Moreover, frequency of band e alone can be used to distinguish the two populations. The high frequency of 3-banded ADH phenotype is a diagnostic mark of the SJ population.

Alcohol Oxidoreductases↗

PubMedDate not supplied

[BAME-Esterase activity in plasmas from blood of human placental interveillous space and umbilical cord vessels (author's transl)].

The authors studied an enzymatic activity (BAME-esterase) from human plasma, intimately related with the bradykinin release mechanisms. The optimal conditions of evaluation of the different plasmas were determined. Lately, the authors showed the results obtained with plasma from maternal peripheral blood, umbilical vessels blood and human placental intervillous space blood. It was concluded: 1. The study of enzymatic kinetics allows to establish a reaction time of 30 minutes, and the enzymatic concentration contained within 0.5 ml. of plasma, as ideal parameters to determine the enzymatic activities into the different compartments. 2. In the cases studied, considered clinically normals, the enzymatic activity in plasma from the interveillous space, before and after the detachment of the placenta, was greater than in peripheral maternal and umbilical vessels bloods. The activity in umbilical artery plasma was greater than in umbilical vein and practically the same as in maternal plasma. 3. The esterase activity values into the compartments studied in pre-eclamptics, were similar to that found in the cases considered clinically normal.

Chorionic Villi↗

PubMed1999

Light and electron microscopic studies on alpha naphthyl acetate esterase activity of peripheral blood T lymphocytes in chicken.

The purpose of this study was to determine the percentage of peripheral blood T lymphocytes and the localization of Alpha Naphthyl Acetate Esterase (ANAE) enzyme at the electron microscopic level in healthy adult chickens by an alpha naphthyl acetate esterase procedure. Peripheral blood samples taken from 30 adult Leghorn breed chickens were used. The percentage of ANAE positive lymphocytes was 56.4 +/- 2.82% (SD). Pseudoeosinophil and eosinophil granulocytes showed a granular positivity. In the electron microscopic examination, ANAE positive reactions were seen in lysosomal granules found in T lymphocytes, pseudoeosinophil, and eosinophil granulocytes.

Animals↗

PubMed2001

Evaluation of fitness components in strains of Drosophila mulleri carrying different genotypes for an esterase.

Several fitness components in strains of Drosophila mulleri carrying the slow or the fast alleles for the major beta esterase (esterase-4) found in this species, as well as in heterozygous flies in which the slow or fast alleles came from one of the parents, were evaluated. Twelve components were analysed including longevity of both virgins and mated males and females, productivity, viability, including the egg-larva, egg-pupa, egg-imago and pupa-imago periods. These parameters were used to estimate the total fitness for each genotype. The best score was reached by individuals having the Est-4S/Est-4S genotype (scored at 1.000), followed by a fitness value of 0.892 presented by the Est-4F/Est-4S genotype (with the fast allele from maternal origin), 0.863 for the Est-4F/Est-4F and 0.842 for the Est-4S/Est-4Fgenotypes (with Est-4F of maternal origin). These results suggested a higher relative adaptability of the Est-4S/Est-4S genotype followed by the Est-4F/Est-4S hybrid that possessed the allele Est-4S of maternal origin, which was incompatible with predictions of neutral polymorphism.

Adaptation, Biological↗