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PubMed1979

Hydrolysis of ester-type drugs by the purified esterase from human intestinal mucosa.

Esterase from human intestinal mucosa was purified 210 fold by solubilization with Triton X-100, chromatography on DEAE-cellulose, Sephadex G-100 and hydroxylapatite, and isoelectric focusing. The purified esterase showed a single band by polyacrylamide gel electrophoresis. The molecular weight of the purified esterase was estimated to be about 55,000 by gel filtration on Sephadex G-150, and the isoelectric point was 5.02. The purified esterase was strongly inhibited by diethyl p-nitrophenyl phosphate (E-600) and diisopropyl fluorophosphate (DFP), and was not inhibited by eserine sulfate and p-chloromercuribenzoate. The purified esterase from human intestinal mucosa was found to be one of the carboxylesterases. The purified esterase hydrolyzed ester-type drugs, i.e., aspirin, clofibrate, indanyl carbenicillin and procaine, but did not hydrolyze amide-type drugs and choline-type drugs.

Aspirin↗
PubMed1995

Nucleotide sequence of the gene for a thermostable esterase from Pseudomonas putida MR-2068.

The esterase gene (est) of Pseudomonas putida MR-2068 was cloned into Escherichia coli JM109. An 8-kb inserted DNA directed synthesis of an esterase in E. coli. The esterase gene was in a 1.1-kb PstI-ClaI fragment within the insert DNA. The complete nucleotides of the DNA fragment containing the esterase gene were sequenced and found to include a single open reading frame of 828 bp coding for a protein of 276 amino acid residues. The open reading frame was confirmed by N-terminal amino acid sequence analysis of the purified esterase. A potential Shine-Dalgarno sequence is followed by the open reading frame. The esterase activity of the recombinant E. coli was more than 200 times higher than that of parental strain, P. putida MR-2068.

Amino Acid Sequence↗
PubMed2004

Differentiation of lactic acid bacteria strains by postelectrophoretic detection of esterases.

Lactic acid bacteria (LAB) comprise a diverse group of Gram-positive, non-spore-forming microorganisms. These bacteria are widely used in food technology. The species identification of LAB depends mainly on physiological and biochemical criteria. The esterolytic systems of LAB remain poorly characterized. Esterases (EC 3.1.1.3) represent a diverse group of hydrolases catalyzing the cleavage and formation of esters bonds Screening of esterases is usually performed either by employing chromophoric substances (e.g., alpha- or beta-naphthyl esters of short-chain fatty acids). The post-electrophoretic detection of esterases is a sensitive technique applied in bacterial systems, that mainly provides information on the similarity of strains within the same species or subspecies according to their esterase patterns. This technique is principally used to determine the number and substrate specificity of esterases and lipases, revealing the complexity of lipase and esterase systems. The present chapter describes the technique of polyacrylamide gel electrophoresis (PAGE; in the absence of sodium dodecyl sulfate [SDS]), in non-denaturing conditions, to find intracellular fractions for strain typing of LAB.

Electrophoresis↗
PubMed2001

Decapitation impacting effect of topically applied chlorpyrifos on acetylcholinesterase and general esterases in susceptible and resistant German cockroaches (Dictyoptera: Blattellidae).

The effect of topically applied chlorpyrifos on acetylcholinesterase and other esterases in heads and decapitated bodies of CSMA and Crawford German cockroaches was examined with spectrophotometric enzyme assay and native polyacrylamide gel electrophoresis. The toxicity of chlorpyrifos was greatly reduced in decapitated CSMA male cockroaches with LD50 value 17.1-fold higher than that of normal CSMA cockroaches. Acetylcholinesterase activity from heads was significantly higher in the Crawford compared with the CSMA strain and did not change until 24 h after chlorpyrifos in vivo treatment in both strains. The p-nitrophenyl butyrate (NPB) esterase activities from both heads and decapitated bodies of the resistant Crawford strain were significantly greater than the susceptible CSMA strain. The p-NPB esterase activity was significantly inhibited by chlorpyrifos in vivo treatment, and total p-NPB esterase activity was significantly reduced in decapitated bodies compared with heads of both strains. Native polyacrylamide gel electrophoresis (PAGE) analysis of extracts solubilized with Triton X-100 from heads and decapitated bodies revealed five major esterase bands and an acetylcholinesterase (AChE) band with a high capability of hydrolyzing alpha-naphthyl butyrate and acetylthiocholine, respectively. In the heads of susceptible CSMA male cockroaches, the activity of mobile isozymes d1 and d2 was completely inhibited at 24 h after chlorpyrifos application, and isozyme e was partially inhibited. In contrast, isozymes c1 and c2 from the decapitated bodies of CSMA cockroaches were mostly affected at 24 h after the topical application of chlorpyrifos. The activities of acetylcholinesterase and esterase isozymes a and b from the decapitated body remained uninhibited in both strains. Inhibition of isozymes d1 and d2 seems to be more important in chlorpyrifos intoxication than acetylcholinesterase.

Acetylcholinesterase↗
PubMed1997

Renal failure and esterase-negative monocytes.

Monocyte esterase deficiency (MED) has been found to be linked with autoimmune (1,2) and lymphoproliferative (2,3) disease. The incidence of MED where > 85% of peripheral blood monocytes are consistently negative in the cytochemical stain for monocyte esterase activity, was shown to be significantly raised in patients with renal failure (3.8%) as compared to the incidence in normal blood donors (0.8%) in a survey performed at the Belfast City Hospital in 1987 (2). The overall occurrence of any proportion of esterase-negative monocytes (ENMs) in patients with renal disease has not been previously studied. The aims of this study were to document this occurrence, and by examining the clinical and biochemical parameters associated with ENMs to identify possible reasons for their occurrence. The original survey data were reexamined and further information previously unreported regarding the occurrence of ENMs was extracted from the renal patient cohort data. Clinical and biochemical data were obtained from the hospital notes of the renal patients and associations sought between these parameters and the occurrence of ENMs. ENMs occurred in a significantly higher proportion (31%) of the renal patients than in the normal population (8%; p < 0.001 chi-sq.) or any other hospital population. A highly significant association between rising serum phosphate levels and increasing proportions of ENMs was identified (p < .001) and this association proved to be independent of serum creatinine levels and renal dialysis status. There is a marked increase in occurrence of esterase-negative monocytes in patients with renal failure. This increase was not caused by the degree of renal failure as reflected by serum creatinine levels, nor by renal transplantation or immunosuppressive therapy. A significant association between rising serum phosphate and increasing proportion of esterase-negative monocytes was identified. This new information, when considered with the previously described experimental and epidemiology evidence for malfunction of esterase negative monocytes, identifies a phenomenon which may contribute to the immunological difficulties of patients with chronic renal failure.

Alkaline Phosphatase↗
PubMed1998

Familiality of monocyte esterase deficiency in patients on continuous ambulatory peritoneal dialysis.

The purpose of this study was to determine whether or not peripheral blood monocyte esterase deficiency occurring in patients on CAPD was a familial characteristic. The peripheral blood monocyte esterase status of 74 patients on CAPD was determined by a naphthyl acetate esterase staining of cytospin preparations of their mononuclear cells following separation over ficoll. The peripheral blood of first degree relatives and spouses of monocyte esterase deficiency patients was similarly investigated for the deficiency. Three patients bad monocyte esterase deficiency and familiality of the defect was demonstrated in two of their families. The third family was incompletely investigated because of lack of consent. The monocyte esterase deficiency demonstrated in this cohort of patients did not result from their renal failure but was a familial characteristic.

Aged↗
PubMed1977

Esterase isozymes of the hen's oviduct.

Esterase isozymes of magnum, isthmus and uterus of three strains of Single Comb White Leghorn hens were examined by zone electrophoresis on starch gels. Although three regions (I, II and III) of esterase activity were observed, the electrophoretic system was optimized to characterize the pattern of up to five zones of esterase activity that were identified in Region I. These esterases were classified as aliesterases based on reactions in the presence of various substrates and inhibitors. No genetic polymorphisms were observed for these isozymes. However, two of these isozymes were perceived to have an electrophoretic mobility slightly faster in patterns of the magnum of layers than in the isthmus, uterus, and magnum of non-layers. It was shown that egg albumen was present in relatively high quantities in the magnum of layers and that egg albumen, when added to supernatant preparations of isthmus, uterus and magnum of non-layers, caused the faster electrophoretic mobility of these two esterase isozymes. No relation between specific gravity of eggs laid by hens and presence of various Region I esterase isozymes could be detected.

Animals↗
PubMed2000

Activation of CPT-11 in mice: identification and analysis of a highly effective plasma esterase.

The camptothecin prodrug CPT-11 (irinotecan, 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin) is converted by esterases to yield the potent topoisomerase I poison SN-38 (7-ethyl-10-hydroxycamptothecin). Recently, a mouse strain (Es1(e)) has been identified that demonstrates reduced plasma esterase activity, and we have monitored the ability of plasma from these mice to metabolize CPT-11. Total plasma esterase activity was reduced 3-fold in Esl(e)mice in comparison to control mice, and this resulted in a 200-fold reduction in SN-38 production after incubation with CPT-11 in vitro. In addition, pharmacokinetic studies of CPT-11 and SN-38 in these animals demonstrated approximately 5-fold less conversion to SN-38. However, extracts derived from tissues from Es1(e) animals revealed total esterase activities similar to those of control mice, and these extracts metabolized CPT-11 with equal efficiency. Northern analysis of RNA isolated from organs indicated that the liver was the primary source of Es-1 gene expression and that very low levels of Es-1 RNA were present in Es1(e) mice. These results suggest that the reduced levels of Es-1 esterase present in Es1(e) mice are due to down-regulation of gene transcription, and that this plasma esterase is responsible for the majority of CPT-11 metabolism in mice.

Animals↗
PubMed2001

Effects of low temperature, cold shock, and various carbon sources on esterase and lipase activities and exopolysaccharide production by a psychrotrophic Acinetobacter sp.

The activities of isocitrate lyase, esterase, and lipase by the psychrotrophic Acinetobacter sp. strain HH1-1 were monitored during incubation at 25 degreesC, 5 degreesC, and after a 25 degreesC to 5 degreesC down shift in growth temperature. During growth at 25 degreesC, isocitrate lyase activity was detected in cell-free extracts, but at 5 degreesC and after cold shock, activity was measured primarily in the cell culture supernatant. Strain HH1-1 produced two cell-associated esterases and an extracellular esterase and lipase. Activities of the extracellular esterase and lipase were reduced when cells were grown at 5 degreesC and after cold shock. In contrast, an increased synthesis of a 53-kDa cell-associated esterase was observed 50 h after cold shock. An extracellular polysaccharide was also produced, indicated by a decrease in surface tension in cell culture supernatant when cells were incubated at 25 degreesC; but like extracellular enzyme activity, production of the exopolymer was reduced when cells were subjected to low temperatures. These results indicated that the intracellular enzyme, isocitrate lyase, leaked out of the cell after cold shock and during growth at 5 degreesC. The increased activity of a cell-associated esterase suggested this enzyme is required for growth at low temperatures. In contrast, activities of extracellular lipolytic enzymes and production of an extracellular polysaccharide were negatively affected at the lower temperatures.

Acinetobacter↗
PubMed2002

Role of esterases and monooxygenase in the deltamethrin resistance in Anopheles stephensi Giles (1908), at Mysore.

Field collected An. stephensi larvae were colonized in the laboratory for 15 generations and acclimatized. An isofemale line was raised from this colony and the larvae were subjected to continuous deltamethrin selection pressure. LC50 and LC90 values were calculated at every generation. The values indicated that at the end of seventh generation the larvae have developed 87 fold tolerance in terms of LC50 value compared with the first generation. The reason for this kind of resistance was analyzed on the basis of differential activity of A-esterase, B-esterase, glutathione s-transferase (GST) and glucose 6-phosphate dehydrogenase (G6PD). A significant correlation (P < 0.05) was observed with B-esterase and G6PD activity with the rise in the LC50 and LC90 values. However no significant rise were observed in the other enzymes tested such as A-esterase and GST. The isozyme analysis of the A-esterase and B-esterase using polyacrylamide gel electrophoresis (PAGE) have shown differential profiles.

Animals↗
PubMed1991

Cytochemical stainings in acute promyelocytic leukemia: chloroacetate esterase reaction as a prognostic index.

Cytochemical studies including peroxidase, sudan black B and esterases were used for staining peripheral blood and bone marrow smears from 42 patients with acute promyelocytic leukemia. The most sensitive methods were sudan black B (mean 98%, range 81-100%) and peroxidase (mean 92% range 70-100%). Naphthol AS-D chloroacetate esterase activity was less sensitive and was positive in only 49.4 per cent (range 2-100%). All of the population of leukemic cells contained less than 3 per cent of alpha-naphthyl acetate esterase staining. For stability tests of the storage specimens compared to fresh stains, there was no difference in naphthol AS-D chloroacetate esterase (mean 45% vs 49% P greater than 0.7) and sudan black B (mean 74% vs 98% P greater than 0.3), but the enzyme activity was significantly decreased in peroxidase staining (mean 42% vs 92% P greater than 0.05). When the patients were divided into 2 groups according to the degree of AS-D chloroacetate esterase activity, those with lower activity had a higher number of white blood cells, promyelocytes and shorter survival compared to those with higher activity. Therefore, naphthol AS-D chloroacetate esterase may be useful as a prognostic index.

Adolescent↗
PubMed2005

Esterase activity in summer population of sunn pest, Eurygaster integriceps Put. (Hemiptera: Scutelleridae).

A key constraint on increasing wheat production in Iran and some neighbouring countries is Sunn pest which cause severe damage to vegetative growth stage of plant in the early season. It also feeds on wheat grain in late growth stage of plants thus damaged wheat grains loose their bakery properties. Because of injecting protease enzymes into the grain during feeding, enzymes degrade gluten proteins and cause rapid relaxation of dough which results in the production of bread with poor volume and texture. Organophosphorus insecticides are the main pesticides used to control the insect pest. However, suitable reduction in pest population has not been achieved partly due to resistance to pesticides. Esterase plays crucial roles in insect physiology and detoxifies a broad range of xenobiotics including insecticides. Enhanced esterase activity is a major mechanism if insecticide resistance and has been detected in a number of insects. To evaluate esterase activity adult bugs were collected from wheat field in Karaj area of Iran and transferred to the laboratory. For biochemical assay, two adult bugs (either males or females) were homogenized in 500 microl Na-phosphate buffer pH 7.2. The homogenates were centrifuged at 14000 g for 10 minutes at 4 degrees C. The supernatants as the enzyme source were pooled and stored at -20 degrees C for later use. For enzyme assay, 300 microl of supernatant was mixed with equal volume of substrates (30 mM alpha-naphthyl acetate or 30 mM beta-naphthyl acetate) and incubated at 30 degrees C for 30 minutes. Then, 50 microl of fast blue solution (150 mg fast blue B in 15 ml distilled water plus 35 ml 5% SDS) was added and esterase activity was determined in a spectrophotometer at 595 nm. Data showed that there are no differences in esterase activity between male and female. However, There was significant differences between hydrolysis of substrates, alpha-naphthyl acetate and beta-naphthyl acetate. Insect esterase hydrolyzes alpha-naphthyl acetate much more than beta-naphthyl acetate.

Animals↗
PubMed1975

The esterase patterns in the ovaries and the embryonated eggs of Aedes aegypti L.

The esterases of Aedes aegypti were studied in the ovary before and during a gonotrophic cycle and also in fully embryonated eggs by means of disc electrophoresis. During oogenesis no significacant changes can be observed besides a marked increase in the total esterase activity. A different esterase pattern is found in eggs after embryogenesis. The electrophoretic mobility of some esterase bands is highly increased in the ovary compared to other organs. One esterase fraction in the ovary and two in the fertilized egg were identified as acetylcholinesterases. All other enzymes are carboxylesterases. The results are compared to those of previous authors and are discussed in view of possible functions of esterases during reproduction.

Acetylcholinesterase↗
PubMed1989

Urinary leukocyte esterase screening test for asymptomatic chlamydial and gonococcal infections in males.

We evaluated the ability of the urinary leukocyte esterase test to predict culture-verified chlamydial and gonococcal urethritis among asymptomatic adolescent males. Nine hundred forty-eight sexually active males provided first-catch urine samples for esterase screening, and 76 (8%) tested positive (greater than or equal to 1+). Among 435 boys who agreed to undergo urethral culture, the esterase was positive in 66 (15%), Chlamydia trachomatis was isolated from 39 (9%), and Neisseria gonorrhoeae was isolated from 14 (3%). The sensitivity, specificity, and positive and negative predictive values for the esterase test were 72%, 93%, and 58% and 96%, respectively. Using the esterase test to screen asymptomatic males for urethritis, we identified 38 culture-verified infections that otherwise would have remained undetected. The urinary leukocyte esterase test is a noninvasive and cost-effective screening method to detect urethritis among asymptomatic adolescent males.

Adolescent↗
PubMed1989

Time of appearance of esterase-positive alveolar macrophages in bovine fetal lung.

Bovine fetal lung tissue was examined histochemically, using alpha-naphthyl butyrate (nonspecific method), to detect the presence of esterase-positive pulmonary alveolar macrophages (PAM). Positively stained PAM were first seen in the alveolar septa and lumina of the lungs of 4 of 8 fetuses 240 days old. Macrophages (n = 100) in 240-day-old fetuses were 6.74 +/- 0.07 microm, and in most cells, esterase-positive granules were sparsely distributed in the cytoplasm. In 10 fetuses 250 days old, the alveolar septa and lumina of lungs contained positively stained macrophages, as did those of all older fetal lungs examined. Compared with macrophages of the 240-day-old fetuses, those (n = 50) of 250-day-old fetuses were significantly larger, 7.32 +/- 0.10 micron (P less than 0.0001), and esterase-positive granules were heavily distributed throughout the cytoplasm. In all fetal lungs, T lymphocytes contained a single, small, esterase-positive granule, compared with the numerous diffuse esterase-positive granules in PAM. Type-II pneumonocytes with well-developed lamellar bodies had no evidence of positive nonspecific esterase reaction in lungs.

Animals↗
PubMedDate not supplied

Species differences in the stereoselective hydrolysis of esmolol by blood esterases.

The stereoselective hydrolysis of esmolol was examined in blood from several species including humans. Blood esmolol esterase activity was in the order of guinea pigs greater than rats greater than rabbits greater than dogs greater than rhesus monkeys greater than humans. Dog and rat blood esterases hydrolyzed the (-)-enantiomer of esmolol faster than the (+)-enantiomer whereas rhesus monkey, rabbit, and guinea pig blood esterases hydrolyzed the (+)-enantiomer faster. Human blood esterases did not demonstrate stereoselectivity. Dog liver esterases also showed stereoselectivity towards the (-)-enantiomer but dog skeletal muscle esterases did not. Studies in mongrel dogs indicated that during esmolol infusions the concentration ratio of (-)-esmolol/(+)-esmolol was approximately 0.85. After termination of the esmolol infusion the (-)/(+) concentration ratio continuously decreased until (-)-esmolol was no longer quantifiable. These results indicate that stereoselective hydrolysis of esmolol occurs in vitro and in vivo.

Adrenergic beta-Antagonists↗
PubMed1987

Antibody-dependent tumour cytolysis by human neutrophils: effect of synthetic serine esterase inhibitors and substrates.

The requirement for serine esterase activity in antibody-dependent cellular cytotoxicity (ADCC) in human neutrophils against Raji target cells has been investigated. The lysis was prevented when the serine esterase inhibitors TPCK and TLCK (chloromethyl-ketone derivatives of tosylamino acids) were introduced into the system. Moreover, neutrophils pretreated with TPCK or TLCK and washed were inhibited as well, via a process unaffected by the presence of adequate amounts of enzymatic substrates. This suggests that the inhibition mediated by TPCK and TLCK is independent of serine esterase blockade, therefore implying the inactivation of some other step crucial to the lysis. The addition of synthetic chymotrypsin substrates (tyrosine and phenylalanine esters) impaired the Raji cell lysis in a dose-related manner without altering the constitution of neutrophil-target conjugates. Trypsin ester substrates were ineffective. These results are in agreement with the involvement of a serine esterase activity with chymotrypsin-like specificity, which should participate in the lysis at a post-binding step. We conclude that neutrophil-mediated ADCC, as developed in our model system, needs the intervention of a serine esterase or esterases, like other systems of cell-mediated cytotoxicity.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1984

[Immunohistochemical findings in intrathoracic tumors. V. Isoenzymes of nonspecific esterases in lung tissue and bronchial cancers].

With histopolyacrylamide electrophoresis (HPAGE) no marked differences in isozyme pattern of non-specific esterase between lung tissue and bronchial carcinomas were found. Only 3 of 19 bronchial carcinomas with histochemically detectable activity of non-specific esterase in tumor tissue showed an additional isozyme with fast mobility. Acetone acts in histochemical reactions as an activator or inhibitor of activity of non-specific esterase. Macrophages, epitheloid cells, and giant cells are inhibited by acetone. In contrast, bronchial epithelial cells are activated by acetone. Bronchial carcinomas showed a different behaviour. Non-specific esterase activity is activated in epidermoid carcinomas but not in adenocarcinomas. This shows close connections to the development of epidermoid carcinomas from bronchial epithelium. Additionally in non-fixed cryostat sections of bronchial epithelium with the aid of non-specific esterase groups of strong reacting cells were demonstrated, which are probably Kultschitzky cells. Acetone inhibits completely activity of esterase in these cells.

Adenocarcinoma↗