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PubMed1991

cDNA cloning and characterization of human monocyte/macrophage serine esterase-1.

Human monocyte/macrophage serine esterase (HMSE), commonly known as acid esterase or alpha-naphthylacetate esterase, comprises a group of five enzyme variants that can be distinguished by their isoelectric points from esterase variants of the other normal human blood cell populations. A cDNA for one of the monocytic enzyme variants (HMSE1) was cloned from a U-937 lambda gt11 cDNA library by screening with an oligonucleotide mixture designed according to amino acid sequence data of the purified enzyme. The cDNA contains 1,727 bp with an open reading frame of 1,512 bp coding for a protein of 503 amino acid residues. HMSE1 cDNA represents the first cloned monocyte/macrophage-specific serine esterase and its sequence shows up to 77% homology to other known serine esterases of different species. The amino acid composition of the putative active site of HMSE1 as deduced from the nucleotide sequence corresponds with the active sites of other serine esterases but not with the active sites of serine proteases. Hybridization of the cDNA with RNA of separated normal blood cell populations and hematopoietic cell lines shows restricted expression within the monocyte/macrophage lineage.

Amino Acid Sequence↗
PubMed1988

[Assessment of cholesterol esterase activity in the duodenal contents of man].

In 20 healthy patients the cholesterol esterase activity in duodenal content was examined. The cholesterol ether of o-coumaric acid was used as a substrate. Increase of the cholesterol esterase activity was noted after stimulation of pancreozymin and secretin. The cholesterol esterase concentration in duodenal content changes in more wide range than the index of the output. The cholesterol esterase output is the most significant informative index. There is not any cholesterol esterase activity in bile, gastric juice and saliva. The results obtained have shown that the main part of the estimated cholesterol esterase activity has a pancreatic base. The investigation of the cholesterol esterase activity in duodenal content may be used in the study of the exocrine function of pancreas.

Adolescent↗
PubMed1988

Esterase profile of human masseter muscle.

The esterase profile of fresh human masseter muscle was investigated by use of histochemistry and electrophoresis. The histochemical methods included reactions for alpha-naphthyl esterase, myofibrillar ATPase, reverse myofibrillar ATPase and succinic dehydrogenase. In frozen sections of the muscle the coloured reaction product for esterases was present both as a diffuse sarcoplasmic coloration and as distinct granules. The intensity of diffuse reaction was used to classify the muscle fibres as strongly, moderately and weakly reacting. The fibres with strong esterase activity belonged to Type I and iiC. iM and Type II A fibres showed a moderate esterase reaction and Type II B fibres had a low activity. The electrophoretic gels stained for esterase activity showed that the human masseter muscle possesses a slow migrating double band with high enzyme activity and a cascade of faster migrating isoenzymes. In isoelectric focused gels the major esterases showed isoelectric points around pH 5.

Esterases↗
PubMed1980

Distribution and activity of esterases in the enteric epithelial cells of certain lepidopteran pests during metamorphosis.

Esterases have been investigated in the enteric epithelial cells of the larva, pupae of varying ages and adult of four Lepidopteran moths--Achoe janata, Atteva fabricella, Hypsa alciforon and Paralellia algira. The foregut epithelium of the larvae, pupas and adults showed negative results for esterases. Positive sites of esterases activity were found in the peripheral region of epithelial cell of the larval midgut: the apical region being free of enzymatic activity. Escape of the enzyme from the cells into the lumen of the midgut was not observed in any of the moths presently investigated. Anterior proctodaeal epithelial cells show appreciable enzymatic activity, while those of posterior hindgut exhibit negative reaction. In prepupal stage the regenerative cells of the midgut epithelium do not show activity of the enzyme at both the apical and peripheral ends. Esterases appear in the regenerative cells after the 2. day of pupal period and thereafter positive results throughout the period of metamorphosis. Activity of the enzyme increases in the midgut digestive cells of newly emerged adult. However in the cells of hindgut epithelium there is no change in the esterases activity or localisation during metamorphosis. The following conclusions have been drawn: 1. Hydrolases investigated are esterases (not lipases) which are present in the enteric epithelium of moths. 2. With the change in the metabolic rate during metamorphosis of insects esterase activity is reduced in epithelial cells at the onset of pupal period, while in pharate as well as newly-emerged adult the enzyme activity increases.

Animals↗
PubMedDate not supplied

[The interaction of phoscarban with the esterases of houseflies and synanthropic cockroaches].

Interactions of phoscarban and its "oxon" with the esterase complex of the house-fly imago and four species of synanthropic cockroaches were studied. Phoscarban and its oxon have a wide spectrum of effects on the esterase complex in cockroaches and flies. These compounds are not specific inhibitors of any of the zones of esterase activity. Their insecticide effect depends on their ability to inhibit both choline esterases, which are responsible for nervous activity, and carboxyl esterases, which are involved in the detoxication of these compounds. We studied the species specificity of the esterase complex, including individual types and fractions, to phoscarban and its oxon in the order Dictyoptera. It was especially distinct for membrane-bound and water-soluble forms of choline esterases.

Animals↗
PubMed1995

Esterase patterns of species in the Drosophila buzzatii cluster.

A comparative analysis was made of the esterase isoenzyme patterns of eight iso-female lines, four of Drosophila serido (B31 D1, A55, B59, Q1, B50Q3), two of D. koepferae (B20D2 and B25D7), one of D. seriema (A95) and one of D. buzzatii (Buz). In all, 43 bands in the spectrum of esterase isoenzymes were detected by electrophoresis in polyacrylamide gels. They showed variations in specific reactions with alpha and beta-naphthyl acetate, number of patterns yielded in their intra-isofemale line combinations, frequencies of such combinations and the thickness and staining degree of some bands, in different individuals, lines and species. Among bands detected exclusively in males, seven may be considered sex-specific (5 alpha-esterases and 2 beta-esterases). These male-specific alpha-esterases have in common the inability to cleave beta-naphthyl acetate in the absence of alpha-naphthyl, denoting a possible common function. The similarity index (SI) and analysis of dependence were calculated in an attempt to quantify the differentiation of the iso-female lines studied, on the basis of esterase bands. SI mean value allowed the separation of the isofemale lines into five classes. Each species had its own pattern of esterase bands, but some bands were shared. A divergence hypothesis for the isofemale lines and the species is discussed.

Animals↗
PubMed1997

Esterase patterns in four Brazilian populations of Haematobia irritans.

Four population samples of Haematobia irritans (horn flies), collected from farms and subjected, or not, to insecticide control, were analysed as to esterase bands by polyacrylamide gel electrophoresis. Eight esterase bands were detected in this species, a low number when compared with flies of other genera. The reduced number of esterase variants of H. irritans is attributed to their parasitic behaviour and blood-dependence for food. Unlike other fly species whose esterase bands exhibit affinity to both alpha- and beta-naphthyl acetates, the esterases in H. irritans seem to be of a single kind, all preferentially hydrolysing alpha-naphthyl. The four populations were very similar as to esterase bands. In relation to the frequencies of patterns resulting from combining bands, Nova Aliança and Birigui were more alike than the other two populations. Inhibitors were used in an attempt to classify five of the esterase bands. The results indicate one acetylcholinesterase, two acetylesterases and two carboxylesterases.

Animals↗
PubMed1999

Detoxication of paraoxon by rat liver homogenate and serum carboxylesterases and A-esterases.

Paraoxon, the active metabolite of parathion, can be detoxified through a noncatalytic pathway by carboxylesterases and a catalytic pathway by calcium-dependent A-esterases, producing p-nitrophenol as a common metabolite. The detoxication patterns of carboxylesterases and A-esterases were investigated in vitro in the present study with a high tissue concentration (75 mg/mL rat liver homogenate or 50% rat serum solution) to more closely reflect enzyme concentrations in intact tissues. A final paraoxon concentration of 3.75 microM was used to incubate with liver homogenates or serum solutions for 5 seconds or 3, 5, 15, or 25 minutes; also 0.625, 1.25, 2.5, 3.125, 3.75, or 5.0 microM paraoxon (final concentration) was incubated with liver homogenates or serum solutions for 15 minutes. Phenyl saligenin cyclic phosphate and EDTA were used to inhibit carboxylesterases and A-esterases, respectively. Significant amounts of p-nitrophenol were generated with or without either inhibitor during a 15 minute incubation with paraoxon from low (0.625 microM) to high (5.0 microM) concentrations. The amount of p-nitrophenol generated via carboxylesterase phosphorylation was greater than via A-esterase-mediated hydrolysis in the initial period of incubation or when incubating with a low concentration of paraoxon. Plateau shape curves of p-nitrophenol concentration versus time or paraoxon concentration indicated that carboxylesterase phosphorylation was saturable. When incubated for long time intervals or with high concentrations of paraoxon, more p-nitrophenol was generated via A-esterase-mediated hydrolysis than from carboxylesterase phosphorylation. The ratio of paraoxon concentration to tissue amount used in in vitro assays of this study was equivalent to dosing a rat with toxicologically relevant dosages. These in vitro data suggest that both carboxylesterases and A-esterases detoxify paraoxon in vivo; carboxylesterases may be an important mode of paraoxon detoxication in initial exposures to paraoxon or parathion before they become saturated, whereas A-esterases may contribute to paraoxon detoxication in repeated exposures to paraoxon or parathion because they will not become inhibited and will remain catalytically active unlike the carboxylesterases. The importance of carboxylesterases in detoxication of paraoxon was verified by an in vivo study. In rats pretreated with tri-o-tolyl phosphate, an in vivo carboxylesterase inhibitor, brain acetylcholinesterase was significantly inhibited after intravenous exposure to parathion. No significant inhibition of brain acetylcholinesterase was observed in rats pretreated with corn oil.

Acetylcholinesterase↗
PubMed1993

Substrate-specific proteases (BLT-esterase) are localized predominantly in the natural killer cells of unprimed mice.

In leukocytes isolated from unprimed mice, the levels of extractable N alpha-Cbz-Lys-thiobenzylesteresterase (BLT-esterase) closely correlated with the number of natural killer (NK) cells. The spleens of mice that exhibit severe combined immunodeficiency (SCID) contained much higher levels of this enzyme than other mouse strains. Treatments that resulted in a local accumulation of NK cells (as assessed by lytic activity) produced a concomitant increase in BLT-esterase activity. However, short-term in vitro treatment of spleen cells with interferon (IFN)-alpha/beta indicated that BLT-esterase levels correlated more closely with absolute numbers of NK cells than with their lytic capacity. There was a very good correlation between the numbers of cells bearing the NK phenotype (NK-1.1+) and BLT-esterase levels. Cells positively sorted using the NK-specific antibodies NK-1.1 and LGL-1 had high enzymatic activity. The BLT-esterase levels were high in both the NK-1.1+/LGL-1- and NK-1.1+/LGL-1+ subsets. Highly purified CD4+ and CD8+ T cells and sIg+ B cells demonstrated negligible enzyme, as did populations of cells highly enriched for macrophages or neutrophils. However, it should be stressed that the inbred mice used on this study have been maintained in a pathogen-free facility. It would be anticipated that mice maintained under less stringent conditions could exhibit appreciable levels of BLT-esterase activity in their T cells. Nonetheless, BLT-esterase is present at high levels in NK cells and cannot be regarded as a T cell-specific enzyme.

Animals↗
PubMed1987

A null allele of esterase D is a marker for genetic events in retinoblastoma formation.

The development of homozygosity or hemizygosity in the 13q14 region by deletion, mitotic recombination, or chromosomal loss has been interpreted as a primary event in retinoblastoma. This finding is consistent with the hypothesis that inactivation of both alleles of a gene located at 13q14.11 is required for tumorigenesis. Observations reported by Benedict and colleagues in one case of bilateral retinoblastoma, LA-RB 69, provided early evidence in favor of this hypothesis. By examining levels of esterase D, an enzyme also mapping to 13q14.11, it was previously inferred that one chromosome 13 was lost. Using a rabbit anti-esterase D antibody and the esterase D cDNA probe, we have found that low but detectable quantities of esterase D protein and enzymatic activity are present in tumor cells from LA-RB 69; fibroblasts from this patient contain two copies of the esterase D gene, indicated by heterozygosity at an Apa I polymorphic site within this gene; and tumor cells from the same patient are homozygous at this site, indicating loss and reduplication of the esterase D locus. These results demonstrate that one of the two esterase D alleles in this patient acted as a "null" or silent allele--that is, was present in the genome with markedly decreased protein expression. This mutant allele acted as a marker for tumor-associated loss of chromosome 13 heterozygosity, in concordance with previous proposals.

Alleles↗
PubMed1980

A method for the ultrastructural demonstration of non-specific esterase in human blood and lymphoid tissue.

Using the substrate 2-naphthylthiol acetate (NTA), we developed a reproducible method of demonstrating a non-specific esterase while retaining nuclear and cytoplasmic details at the ultrastructural level. The NTA esterase had a distribution and pattern of staining similar to those of esterases demonstrable at the light microscopic level by the alpha-naphthyl acetate or naphthol AS-D acetate esterase reaction. The NTA esterase appeared as intensely electron-dense granules of varying size and shape in the cytoplasm. The granules were most abundant in the cells of the histiomonocytic series. The large number of diffusely scattered granules in the cytoplasm of the histiocytes and monocytes made it possible to separate these cells from other haematopoietic elements. There was usually no direct relationship between the NTA esterase positivity and the amount or the location of lysosomes or mitochondria, although in some histiocytes the granules appeared to be associated with lysosomes. The NTA esterase-positive granules were usually more numerous than lysosomes and were located outside the lysosomal granules. Some of the lymphocytes outside the germinal centres and most of the lymphocytes in the blood showed a punctate positivity in the form of 1--4 electron-dense dots. Plasma cells were usually negative but, in rare cases, contained an occasional single dot-like reaction product similar to that in some of the lymphocytes. Granulocytes were always negative. The method described in this paper can be used effectively for identification and study of human haematopoietic cells lines at the ultrastructural level.

Carboxylic Ester Hydrolases↗
PubMed1988

Purification and characterization of a non-kallikrein arginine esterase from dog urine.

A non-kallikrein arginine esterase (esterase I) has been purified from dog urine and characterized. The enzyme was purified by a three-step procedure, including ion exchange chromatography on DEAE-Sephacel, affinity chromatography on p-aminobenzamidine-Sepharose, and final gel filtration on Ultrogel AcA-54. The purified preparation gave three protein bands on polyacrylamide gel electrophoresis, all of which had esterolytic activity. The enzyme has a specific activity of 601 esterase units/mg protein. It has negligible kininogenase activity. Esterase I gave two closely migrating protein bands on reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis with molecular weights of 34,000 and 33,300. Esterase I is a glycoprotein with a pH optimum of 9.5 and a pI of 4.62. The enzyme is strongly inhibited by a host of inhibitors including aprotinin, leupeptin, antipain, soybean trypsin inhibitor, lima bean trypsin inhibitor, and DPhe-Phe-Arg-chloromethyl ketone (I50 in the 10(-9)-10(-8) M range). However, p-aminobenzamidine, N alpha-p-tosyl-lysyl chloromethyl ketone and phenylmethylsulfonyl fluoride were weak inhibitors, with I50 values in the 10(-5)-10(-7) M range. The enzyme preferentially hydrolyzes Pro-Arg bonds. Among fluorogenic substrates used in this study, butyloxycarbonyl-Val-Pro-Arg-methylcoumarinamide (alpha-thrombin substrate) was found to be the best, with a Km of 1.7 microM and a kcat/Km of 6.3 s.microM-1. However, esterase I does not convert fibrinogen to fibrin nor activate plasminogen to plasmin. Esterase I is immunologically distinct from dog urinary kallikrein, having no cross-reactivity with antibodies against dog kallikrein.

Amino Acids↗
PubMed2004

Enzyme-coupled assay of acetylxylan esterases on monoacetylated 4-nitrophenyl beta-D-xylopyranosides.

Three different monoacetates of 4-nitrophenyl beta-D-xylopyranoside were tested as substrates for beta-xylosidase and for microbial carbohydrate esterases and a series of non-hemicellulolytic esterases. The acetyl group in 2-O-acetyl, 3-O-acetyl, and 4-O-acetyl 4-nitrophenyl beta-D-xylopyranoside makes the glycoside resistant to the action of beta-xylosidase (EC 3.2.1.37). This fact was explored to introduce a new enzyme-coupled assay of acetylxylan esterases (EC 3.1.1.72) and other carbohydrate-deacetylating enzymes. The deacetylation converts the monoacetates into the substrate of beta-xylosidase, the auxiliary enzyme. The effect of the acetyl group migration along the xylopyranoid ring in aqueous media can be avoided by shortening the assay duration. The assay enables an easy examination of the positional specificity of the enzymes, which is important for classification of acetylxylan esterases and for elucidation of the structure-function relationship among carbohydrate esterases in general. Non-hemicellulolytic esterases showed different positional specificity of deacetylation than did acetylxylan esterases.

Acetates↗
PubMed2004

Comparison of mesophilic and thermophilic feruloyl esterases: characterization of their substrate specificity for methyl phenylalkanoates.

The active sites of feruloyl esterases from mesophilic and thermophilic sources were probed using methyl esters of phenylalkanoic acids. Only 13 out of 26 substrates tested were significant substrates for all the enzymes. Lengthening or shortening the aliphatic side chain while maintaining the same aromatic substitutions completely abolished activity for both enzymes, which demonstrates the importance of the correct distance between the aromatic group and the ester bond. Maintaining the phenylpropanoate structure but altering the substitutions of the aromatic ring demonstrated that the type-A esterase from the mesophilic fungus Fusarium oxysporum (FoFaeA) showed a preference for methoxylated substrates, in contrast to the type-B esterase from the same source (FoFaeB) and the thermophilic type-B (StFaeB) and type-C (StFaeC) from Sporotrichum thermophile, which preferred hydroxylated substrates. All four esterases hydrolyzed short chain aliphatic acid (C2-C4) esters of p-nitrophenol, but not the C12 ester of laurate. All the feruloyl esterases were able to release ferulic acid from the plant cell wall material in conjunction with a xylanase, but only the type-A esterase FoFaeA was effective in releasing the 5,5' form of diferulic acid. The thermophilic type-B esterase had a lower catalytic efficiency than its mesophilic counterpart, but released more ferulic acid from plant cell walls.

Binding Sites↗
PubMed1986

Purification and characterization of a serine protease (esterase B) from rat submandibular glands.

A new protease has been purified to homogeneity from rat submandibular gland homogenate by using DEAE-Sephadex chromatography, chromatofocusing, aprotinin-Sepharose affinity chromatography, and high-performance liquid chromatography. The enzyme has been named esterase B, since it represents the second major esterolytic peak on DEAE-Sephadex chromatography of submandibular gland homogenate. It is an acidic protein (pI = 4.45) with an apparent molecular weight of 27 000. It is heat-stable and has an optimum pH of 9.5. Esterase B hydrolyzed the synthetic substrates tosyl-L-arginine methyl ester and Val-Leu-Arg-p-nitroanilide (S2266). It also cleaved dog plasma kininogen to produce a kinin, identified as bradykinin on reverse-phase high-performance liquid chromatography. Esterase B, however, is only a weak kininogenase, since it had only 5% of the kininogenase activity of equimolar concentrations of glandular kallikrein and had no effect on rat mean blood pressure or on the isolated rat uterus. Esterase B activated plasminogen and had caseinolytic activity. It was inhibited by aprotinin, soybean trypsin inhibitor, lima bean trypsin inhibitor, phenylmethanesulfonyl fluoride, antipain, leupeptin, and p-tosyl-L-lysine chloromethyl ketone. On double immunodiffusion, when reacted with kallikrein and tonin antisera, esterase B showed partial identity with kallikrein but not with tonin. On immunoelectrophoresis against kallikrein antisera, esterase B formed a precipitin arc at a position different from that of kallikrein. Esterase B appears to be a trypsin-like serine protease having some homology with glandular kallikrein.

Amino Acids↗
PubMed1994

Causes and consequences of esterase 6 enzyme activity variation in pre-adult Drosophila melanogaster.

We report heritable threefold differences in both larval and pupal esterase 6 activity among 17 isoallelic lines of D. melanogaster extracted from a natural population. The activity differences in the two stages are only weakly correlated with each other or with previously determined values for esterase 6 activity in adults of these lines. The pre-adult activity variation is also unrelated to polymorphisms among the lines for six esterase 6 allozymes and six restriction sites in a region encompassing the esterase 6 coding DNA and the first kbp of 5' flanking DNA. However, two insertions, of 8.0 and 6.8 kbp, located about 1.4 kbp 5' of the esterase 6 coding region are associated with low activity in larvae and, to a lesser extent, in pupae, albeit not in adults. Restriction mapping reveals similarity between the 8.0 kbp insert and the 7.4 kbp retrotransposon 17.6. The differences in larval activity among lines are positively correlated with fitness as assessed from assays of pre-adult viability and development time but no significant associations between pupal esterase 6 activity and these measures are detected. Some effects of esterase 6 allozyme differences are also found for viability and development time but these effects could be explained by linkage disequilibrium between the 8.0 kbp insert and the EST6-9 allozyme.

Adaptation, Biological↗
PubMed1995

The same esterase B1 haplotype is amplified in insecticide-resistant mosquitoes of the Culex pipiens complex from the Americas and China.

In Culex pipiens, overproduction of nonspecific esterases is a common mechanism of resistance to organophosphate insecticides. The esterases are attributed to closely linked loci named A and B, and overproduction of all esterases B is due to gene amplification. In order to determine if the esterase B1 identified by electrophoretic studies in Culex pipiens mosquitoes from different countries is overproduced due to the amplification of the same DNA haplotype, the amplified region encompassing the structural esterase B1 gene was characterized by restriction mapping and RFLP. The same amplified haplotype was found in mosquitoes with an esterase B1 protein, independently of their geographical origin: French Guiana, Venezuela, Puerto Rico, California and China. Large variations in amplification levels were observed. It is concluded that B1 amplification has a unique origin, either in America or in Asia, and has subsequently spread by migration. This migration is more limited than that of A2-B2 esterases, since B1 is confined to the Americas, the Caribbean and part of China, whereas the A2-B2 distribution now includes the Americas, the Caribbean, Asia, Africa, the Pacific Islands and Europe.

Americas↗
PubMed1997

Purification and characterization of a feruloyl esterase from the fungus Penicillium expansum.

An extracellular phenolic acid esterase produced by the fungus Penicillium expansum in solid state culture released ferulic and rho-coumaric acid from methyl esters of the acids, and from the phenolic-carbohydrate esters O-[5-O-(trans-feruloyl)-alpha-L-arabinofuranosyl]-(1-->3)-O-beta- D-xylopyranosyl-(1-->4)-D-xylopyranose (FAXX) and O-[5-O-((E)-rho-coumaroyl)-alpha-L-arabinofuranosyl]- (1-->3)-O-beta-D-xylopyranosyl-(1-->4)-D-xylopyranose (PAXX). The esterase was purified 360-fold in successive steps involving ultrafiltration and column chromatography by gel filtration, anion exchange and hydrophobic interaction. These chromatographic methods separated the phenolic acid esterase from alpha-L-arabinofuranosidase, pectate and pectin lyase, polygalacturonase, xylanase and beta-D-xylosidase activities. The phenolic acid esterase had an apparent mass of 65 kDa under non-denaturing conditions and a mass of 57.5 kDa under denaturing conditions. Optimal pH and temperature were 5.6 and 37 degrees C, respectively and the metal ions Cu2+ and Fe3+ at concentrations of 5 mmol 1-1 inhibited feruloyl esterase activity by 95% and 44%, respectively, at the optimum pH and temperature. The apparent Km and Vmax of the purified feruloyl esterase for methyl ferulate at pH 5.6 and 37 degrees C were 2.6 mmol 1-1 and 27.1 mumol min-1 mg-1. The corresponding constants of rho-coumaroyl esterase for methyl coumarate were 2.9 mmol 1-1 and 18.6 mumol min-1 mg-1.

Carboxylic Ester Hydrolases↗