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PubMed2003

Variations in the normal activity of esterases in plasma and liver of camels (Camelus dromedarius), cattle (Bos indicus), sheep (Ovis aries) and goats (Capra hircus).

Esterases are a large group of enzymes found in plasma (or serum) and tissues, which hydrolyse a number of xenobiotics. Some of these enzymes have not yet been measured in tropical domestic animals. In the present work, we have measured the activities of three esterases, viz. aspirin esterase, cholinesterase and nitrophenylacetate esterase in the plasma and livers of male and female camels, cattle, sheep and goats. The results indicate that the enzyme activities are highest in the goat, followed by sheep and cattle (which showed broadly similar activities), and lowest in camels. Gender had no statistically significant effect, although males exhibited about 5-8% more enzyme activity in each of the four species, than females.

Animals↗
PubMed1984

Sex difference in cholesterol esterase activity in rats adipose tissues and changes of the activity following orchiectomy and ovariectomy.

Sex differences in cholesterol esterase activity and changes in the activity in response to orchiectomy and ovariectomy were investigated in rat adipose tissue in association with serum lipid levels. Cholesterol esterase activity in the parametrial adipose tissue was 65% higher than that in the epididymal adipose tissue, but there were no sex differences in the activity of subcutaneous and perirenal adipose tissue. Pre- and post-pubertal orchiectomy resulted in a marked enhancement of cholesterol esterase activity, whereas ovariectomy significantly reduced the activity. Serum cholesterol and triacylglycerol levels were elevated through orchiectomy but ovariectomy had no effect. These results suggest that cholesterol esterase activity in the adipose tissue around sexual organs is regulated by gonadal hormones and that the increase in serum cholesterol due to orchiectomy is unlikely to be related to the change in the enzyme activity.

Adipose Tissue↗
PubMed1972

Detection of maternal esterase in mouse embryonic tissues.

A genetic variant of esterase in mice is used to demonstrate for the first time that an enzyme of maternal origin is taken up intracellularly by two mid-gestation tissues dervied from the embryo: trophoblast and yolk sac (visceral endoderm). Although other alternatives are still possible, it is likely that the esterase is transported from the mother to the trophoblast via the serum. If so, the phenomenon is selective, since at least one other prominent serum esterase is not found in trophoblast or yolk sac cells. The enzyme has not been detected in the embryo proper, even at very late stages of pregnancy. Trophoblast cells-developing from blastocysts implanted under the kidney capsule of a male mouse also appear to have the ability to take up host esterase. Efforts to demonstrate uptake of the enzyme by trophoblast cells in blastocyst cultures have been unsuccessful.

Animals↗
PubMed2004

Peptide mapping identifies hotspot site of modification in human serum albumin by methylglyoxal involved in ligand binding and esterase activity.

Methylglyoxal is a potent glycating agent under physiological conditions. Human serum albumin is modified by methylglyoxal in vivo. The glycation adducts formed and structural and functional changes induced by methylglyoxal modification have not been fully disclosed. Methylglyoxal reacted with human serum albumin under physiological conditions to form mainly the hydroimidazolone N(delta)-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (92% of total modification) with a minor formation of argpyrimidine, N(epsilon)-(1-carboxyethyl)lysine, and methylglyoxal lysine dimer. When human serum albumin was modified minimally with methylglyoxal, tryptic peptide mapping indicated a hotspot of modification at Arg-410 located in drug-binding site II and the active site of albumin-associated esterase activity. Modification of Arg-410 by methylglyoxal was found in albumin glycated in vivo. Other sites of minor modification were: Arg-114, Arg-186, Arg-218, and Arg-428. Hydroimidazolone formation at Arg-410 inhibited ketoprofen binding and esterase activity; correspondingly, glycation in the presence of ketoprofen inhibited Arg-410 modification and loss of esterase activity. The pH dependence of esterase activity indicated a catalytic group with pK(a) = 7.9 +/- 0.1, assigned to the catalytic base Tyr-411 with the conjugate base stabilized by interaction with the guanidinium group of Arg-410. Modification by methylglyoxal destabilized Tyr-411 and increased the pK(a) to 8.8 +/- 0.1. Molecular dynamics and modeling studies indicated that hydroimidazolone formation caused structural distortion leading to disruption of arginine-directed hydrogen bonding and loss of electrostatic interactions. Methylglyoxal modification of critical arginine residues, therefore, whether experimental or physiological, is expected to disrupt protein-ligand interactions and inactivate enzyme activity by hydroimidazolone formation.

Amino Acid Sequence↗
PubMed1981

Age-dependent changes in esterases of Callosobruchus maculatus Fab. (Bruchidae: Coleoptera).

Age-dependent changes, quantitative as well as qualitative, in esterase activity were found by assaying crude extracts of Callosobruchus maculatus. There is increase in esterase activity in both the sexes with advancing age in bruchids. Esterase from old bruchids showed several additional electrophoretic bands which did not appear in assays of young bruchids; in addition there is an increase in staining intensity of the bands. A rapid increase in esterase activity during the last days of life may be responsible for producing energy used in various metabolic processes in an attempt to escape death.

Aging↗
PubMed1968

Mechanisms of activation of C'1 esterase in hereditary angioneurotic edema plasma in vitro.

The generation of C'1 esterase activity in siliconed plasma obtained from individuals with hereditary angioneurotic edema in remission tends to occur spontaneously, but can be hastened during its incubation with preparations of activated Hageman factor. This effect of activated Hageman factor could not be shown during its incubation with normal siliconed plasma, nor could consumption of normal serum inhibition of C'1 esterase be clearly shown. Soy bean trypsin inhibitor and heparin could impair this enhanced generation of C'1 esterase but neither inhibits the esterolytic function of C'1 esterase once formed. Trasylol was less effective in blocking this effect of activated Hageman factor. While the mechanism of the effect of activated Hageman factor upon C'1 activation remains obscure, it is apparent that some intermediate steps, possibly involving a kinin-forming system of plasma, may play a role.

Angioedema↗
PubMed1988

Serine esterase and hemolytic activity in human cloned cytotoxic T lymphocytes.

Target cell lysis by most murine cytotoxic T lymphocytes appears to be mediated by a complement (C9)-like protein called perforin, contained in high-density cytoplasmic granules. These granules also contain high levels of serine esterase activity, which may also play a role in cytolysis. Analysis of 17 cloned human cytotoxic T lymphocytes revealed the presence of serine esterase that is very similar to its murine counterpart in substrate and inhibitor specificities, pH optimum, and molecular mass; dot blot hybridization with synthetic oligonucleotides corresponding to the active sites of two known murine CTL esterases suggests homology to the murine enzyme HF. However, serine esterase was present at only approximately 10% of the level found in murine CTLs, and was not secreted during CTL-target cell interaction; moreover, hemolytic activity could not be detected in any of the seven cell lines tested. The results suggest that the human CTLs examined here kill their target cells by a mechanism different from that used by most cloned murine CTLs.

Cell Line↗
PubMed2001

Relationship between age and plasma esterases.

INTRODUCTION: the older population is the most medicated. Despite high drug usage, older people are generally excluded from the research underpinning new drug development. This means that drugs are prescribed to older people with very little understanding of how they are likely to metabolize them. More research is needed to investigate the possible effects of ageing on the biotransformation of drugs. We therefore undertook a cross-sectional study examining the effect of age on the activities of benzoylcholinesterase, butyrylcholinesterase, acetylcholinesterase and aspirin esterase. METHODS: we measured the activities of benzoylcholinesterase and butyrylcholinesterase in 70 healthy volunteers aged 18-85 years. We measured the activities of acetylcholinesterase and aspirin esterase in 43 healthy volunteers aged 18-85 years. We determined plasma activities of benzoylcholinesterase, butyrylcholinesterase, acetylcholinesterase and aspirin esterase spectrophotometrically. RESULTS: we found no correlation between the activities of any of the enzymes measured and advancing age. CONCLUSION: age per se is not associated with reductions in the activities of esterase enzymes.

Acetylcholinesterase↗
PubMed1977

Esterase activity in erythroleukemia.

Specific esterase activity, a property generally ascribed to cells of granulocytic origin, was found in abnormal erythroid precursors obtained from the bone marrows of six patients with untreated erythroleukemia. These erythroblasts also showed nonspecific esterase activity. Neither specific nor nonspecific esterase activity was detected in erythroid precursors obtained from the bone marrows of ten presumed normal individuals. The implications of finding specific esterase activity in the erythroblasts of erythroleukemia are discussed.

Erythroblasts↗
PubMed1976

Linkage relationships and chromosome assignment of four esterase loci in the mosquito Anopheles albimanus.

Although anopheline mosquitoes are important vectors of malaria, their genetic makeup has not yet been extensively investigated. The present studies concentrate on the genetic basis of esterases in Anopheles albinomanus. Nine zones of esterase activity activity have been resolved by gel electrophoresis. Four of these esterases: EST-2, EST-4, EST-6, and EST-8 are present throughout all developmental stages and also posess allelic variation. Mass matings were carried out with homozygous males and females heterozygous for two or more loci. The analyses of the progeny from single egg batches revealed that the four esterase systems mentioned above are encoded in separate loci with codominant allels. Analyses of two-point and three-point crosses have indicated the following linkage relationships: Est-8--12%--Est-4--22%--Est-2--9%--Est-6. The assignment of this linkage group to chromosome 3 has been accomplished by the use of a Y-2 chromosome translocation.

Alleles↗
PubMed1998

Comparison of esterases between life stages and sexes of resistant and susceptible strains of German cockroach (Dictyoptera: Blattellidae).

Esterase activity between the resistant Crawford and susceptible CSMA strains of German cockroach, Blattella germanica (L.), was compared with the substrates alpha- and beta-naphthyl acetate across sex and nymphal age classes. Esterase isozyme analysis with native polyacrylamide gel electrophoresis also was conducted to identify quantitative and qualitative differences between strains, sexes, and age classes. The Crawford strain was highly resistant to cypermethrin, propoxur, and permethrin with a resistant ratio (RR) of 17.26, 15.75, and 13.53, respectively, and mildly resistant to chlorpyrifos (RR 5.62). The alpha-NA and beta-NA esterase activities in the Crawford strain were significantly higher than those activities in the CSMA strain in both nymphal and adult stages. In the Crawford strain, the enzyme activity in nymphs was significantly higher than that in adults, but such differences were not observed in the CSMA strain. The mobile isozymes a and c stained more intensely than others in every developmental stage and sex of both strains but showed greater intensity in the Crawford strain. Another intensely stained isozyme b was observed only in the homogenates from the Crawford strain. The combination of isozyme b and the overproduced isozyme a and c in the Crawford strain seems to be responsible for the difference in total esterase activity between the CSMA and Crawford strains.

Animals↗
PubMed1976

In vitro stimulation by retinol of porcine pancreatic esterase activity toward esters of short-chain fatty acids.

1. Retinol exerted a remarkable stimulating effect (approx. 260% increase), essentially similar to that (300%) of phytol, on the so-called esterase activity displayed by crude pancreatic lipase [EC 3.1.1.3] toward true solutions of esters, but none of the typical lipase activity toward emulsions of water-insoluble esters. 2. Comparison of the stimulatory effects of retinol derivatives on the esterase activity revealed that retinyl acetate was the most active, being sustantially similar in effect to retinol; retinal was fairly active, while retinoic acid, retinyl palmitate, and beta-ionone were far less active. 3. With various isoprenoid compounds, the efficiency of stimulation increased with the carbon chain length, attaining a maximum at 15 to 20 carbon atoms. Above this chain length the efficiency decreased rapidly. 4. Comparison of the effects of retinol and phytol on the esterase activity of various other lipolytic enzymes indicated that this kind of activator may be relatively specific to porcine pancreatic esterase activity.

Candida↗
PubMed1980

Distinctive electrophoretic patterns of esterases from Klebsiella pneumoniae, K. oxytoca, Enterobacter aerogenes and E. gergoviae.

Esterases of 14 strains of Klebsiella pneumoniae, 14 strains of K. oxytoca, 16 strains of Enterobacter aerogenes and 16 strains of E. gergoviae were analysed by horizontal electrophoresis in polyacrylamide-agarose gel. Four principal esterase bands (designated E1 to E4) and nine minor bands differing in their activity towards synthetic substrates and in their sensitivity to heat and to di-isofluoropropyl phosphate were defined. The comparative distribution of bands showed that the four species analysed were characterized by distinct electrophoretic patterns of their esterases. Band E1 was found in all four species, bands E2 and E3 only in K. oxytoca and band E4 only in some strains of E. gergoviae. The apparent molecular weights of esterases E2 and E3, determined by electrophoresis in a 4 to 30% polyacrylamide gradient gel, were 58000 (+/- 1000) and 72000 (+/- 1800), respectively.

Electrophoresis, Polyacrylamide Gel↗
PubMed1986

Characterization of Enterobacter cloacae and E. sakazakii by electrophoretic polymorphism of acid phosphatase, esterases, and glutamate, lactate and malate dehydrogenases.

Acid phosphatase, esterases, and glutamate, lactate and malate dehydrogenases of 34 strains of Enterobacter cloacae and 22 strains of Enterobacter sakazakii were analysed by horizontal polyacrylamide agarose gel electrophoresis and by isoelectrofocusing in thin-layer polyacrylamide gel. The two species could be separated on the basis of distinct electrophoretic patterns of all enzymes analysed. Glutamate dehydrogenase and acid phosphatase were detected exclusively in E. cloacae, whereas esterase bands were more intensively stained in E. sakazakii. For each species, two zymotypes could be distinguished, on the basis of electrophoretic mobilities of malate dehydrogenase and banding patterns of esterase for E. cloacae, and by both isoelectric point and electrophoretic mobilities of an esterase and of lactate and malate dehydrogenases for E. sakazakii. The high degree of enzyme polymorphism within the two species permitted precise identification of strains. The variations in electrophoretic patterns might therefore provide useful epidemiological markers.

Acid Phosphatase↗
PubMed1987

Differentiation of Shigella by esterase electrophoretic polymorphism.

The electrophoretic mobilities of four esterases (A, B, C, and I) of 182 strains of Shigella dysenteriae, S. flexneri, S. boydii and S. sonnei were compared to those of 636 strains of Escherichia coli from various origins, including the Alkalescens Dispar group and enteroinvasive strains. Discriminant analysis of the distribution of esterases among the strains revealed that Shigella could be distinguished from E. coli by differences in the distribution of allozymes of esterases C and I. Principal components analysis distinguished four major clusters of Shigella strains corresponding to the following: S. dysenteriae serotype 1; S. flexneri serotypes 1 to 5; S. flexneri serotype 6 and S. boydii serotypes 2 and 4; and S. sonnei. The last three were characterized by distinct electrophoretic variants of carboxylesterase B, as judged by the two-dimensional electrophoretic profile and titration curves. The distinct esterase pattern obtained for the strains of S. boydii serotype 13 substantiates the view that this serotype may constitute a new species.

Electrophoresis, Polyacrylamide Gel↗
PubMed1990

Characterization of enterobacteria by esterase specific-activity profiles.

The spectrum of specific activities and the electrophoretic mobilities of esterases produced by 550 strains of Enterobacteriaceae belonging to 36 species and subclassified into six groups (group 1, Escherichia coli, Shigella and Escherichia hermanii; group 2, genus Salmonella and genus Citrobacter; group 3, genus Klebsiella and genus Enterobacter; group 4, genus Serratia and Serratia fonticola; group 5, genus Proteus, genus Providencia and genus Morganella; and group 6, genus Yersinia) were analysed by acrylamide/agarose gel electrophoresis using standardized methods for staining and mobility comparisons. Nineteen types of esterase were defined by their respective esterase specific-activity profile (ESAP). A multiple correspondence analysis (MCA) of the ESAP data enabled 82% of the strains in the 36 species to be correctly classified. In each group, the species were clearly delineated after MCA on both ESAP and electrophoretic mobility data. In addition, the smallest number of characters providing species identification of Yersinia strains by esterase polymorphism was identified by means of a binary segmentation tree technique.

Enterobacteriaceae↗
PubMed1977

Relationships between electrophoretic patterns of esterases from Salmonella.

Esterases of 85strains of the four biochemically-defined subgenera of Salmonella, when analysed by the acrylamide-agarose zymogram technique using several synthetic substrates, gave four principal bands (E1, E2, E3, E4) and two minor ones. The E1 esterase band hydrolysed alphs-naphthyl acetate, whereas the E2 band hydrolysed beta-naphthyl acetate. These bands were resistant to di-isofluoropropyl phosphate (DFP) and their electrophoretic distribution among the strains occurred within a relatively small MF range, MF being the distance moved by the esterase band as a percentage of the distance moved by the dye front. The E3 band hydrolysed alpha-naphthyl acetate and alpha-naphthyl napbuyyrate and, to a lesser degree, beta-naphthyl esters, whereas the E4 band hydrolysed alpha-naphthyl acetate. These bands were sensitive to DFP and their electrophoretic distribution among the strains occurred in a wide MF range. ALL Salmonella strains were closely related in terms of their esterase profiles. However, the divergences in electrophoretic distribution of bands E3 and E4 were sufficient to recognize the subgenera of most of the Salmonella strains analysed.

Electrophoresis, Agar Gel↗
PubMed1977

Distinctive electrophoretic patterns of Esterases from Levinea malonatica, Levinea amalonatica and Citrobacter.

Esterases of 42 strains of Levinea malonatica, Levinea amalonatica and Citrobacter were analysed by horizontal slab electrophoresis in polyacrylamide-agarosegel using several synthetic substrates. On the basis of esterase zymograms a distinctive pattern was established for each of the three species. Levinea malonatica was characterized by two major bands: one hydrolysing acetate esters but not butyrate esters; and the other hydrolysing alpha-naphthyl acetate and reacting weakly with alpha-naphthyl butyrate and beta-naphthyl acetate. Levinea amalonatica showed one prominent band that hydrolysed alpha-naphthyl esters and reacter weakly with beta-naphthyl esters. Citrobacter strains showed one major band that hydrolysed alpha-naphthyl esters and appeared slightly more towards beta-naphthyl esters than that of L. amalonatica. Considerable variations in electrophoretic mobility were observed among Citrobacter strains. Levinea amalonatica was less variable. In addition, one minor anodal band reacting with beta-naphthyl acetate was observed in both L. malonatica and Citrobacter. The relative molecular sizes of the major esterase bands were determined by disc electrophoresis with gels of different acrylamide concentrations. The molecular size of the major band of Citrobacter appeared to be smaller than that of the corresponding esterase band of L. amalonatica.

Citrobacter↗