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At least 955 records · Page 53Linked to original sources
PubMed1982

Linkage studies on an esterase locus in the mosquito Aedes togoi.

An electrophoretic survey of esterases in 7 wild-type and 10 mutant strains of the mosquito Aedes (Finlaya) togoi was undertaken using thin-layer agar gels. Three esterases (Designated the Est-1, Est-2, and Est-3 loci in decreasing order of electrophoretic mobility) could be detected from fourth-instar larvae, pupae, and 2- to 5-day-old adults. Homogenates of the larvae gave the most intensely stained bands in the gels, especially for Est-3. The three esterases were designated carboxylesterases based on their responses to the two esterase inhibitors, eserine and paraoxon (diethyl-p-nitrophenyl phosphate). The Est-3 locus was found to have alleles including at least one null. The linkage results of six backcrosses suggest that Est-3 is located only 5-8 map units from the sex allele (m) and the gene arrangement is Est-3-m-s (straw colored larva) in linkage group I.

Aedes↗
PubMed1985

Biochemical properties, homology, and genetic variation of Drosophila "nonspecific" esterases.

The biochemical properties and tissue distribution of two major, soluble "nonspecific" esterases have been studied in Drosophila melanogaster, D. pseudoobscura, and related species. The "alpha-like" activity is due to a monomer enzyme (MW congruent to 60 kd) having a nonspecific tissue distribution, which was inhibited by p-hydroxymercuribenzoate (5 X 10(-4)M) plus eserine (1 X 10(-5)M) and was relatively unstable during polyacrylamide gel electrophoresis. Electrophoretograms of this enzyme could be enhanced by treating gels with beta-mercaptoethanol before staining. This procedure allowed the identification of a new alpha-esterase (Est-4) in D. pseudoobscura. The "beta-like" esterase activity (EC 3.1.1.1) is due to a dimer (MW congruent to 120 kd) in most Drosophila species. D. melanogaster and its siblings (D. simulans and D. mauritiana) were exceptions in which this enzyme had an unusual tissue distribution (increased activity in the male reproductive system) and was a monomer (MW congruent to 60 kd). Differences in the genetic variability of these esterases are discussed and interpreted by a population expansion model rather than by differences in biochemical properties of enzyme forms.

Animals↗
PubMed1990

An analysis of molecular polymorphism of esterase M produced by motile Aeromonas strains.

The high levels of electrophoretic polymorphism of esterase M detected in eight distinct hybridization groups of motile Aeromonas raise questions of genetic homogeneity of the electromorphs. The 40 electromorphs detected fall in four Mr classes--75, 80, 90, and 110 kD--and one typical variant belonging to each of these classes was purified. The four purified esterases exhibited the same resistance to heat, to pH and to diisopropyl fluorophosphate, the same Km values for 1-naphthyl acetate and 1-naphthyl propionate (1 mM), and immunological cross-reactions. Within each class, the electromorphs appeared to be related in term of single amino acid substitutions as estimated from their comparative titration patterns. The titration curves of the four purified esterases were strictly parallel suggesting close structural similarities. Thus, despite considerable variation in their pI, MF, and Mr values, it seems likely that the variants of esterase M are the products of closely related loci originating from a common ancestral gene.

Aeromonas↗
PubMed1988

Genetic variation as a tool for histochemical localization of a nonspecific esterase.

A prominent esterase activity was demonstrated histochemically in the straight portion of the proximal tubules in kidney of the mouse strain DBA/2J after inhibition with bis-p-nitrophenyl phosphate and subsequent staining, using 5-bromoindoxyl acetate as substrate. In the strain PUC/1Fre, the corresponding esterase was only weakly expressed. By comparing data from the literature (von Deimling et al. 1981) with the characteristic features of this kidney esterase including substrate preference, sensitivity to inhibitors, solubility, histochemical location, and strain differences, it was concluded that it was identical with the previously electrophoretically defined esterase-16.

Animals↗
PubMed1989

Plasma esterase-1 (ES-1) activity is increased in rats fed high-fat diets.

The question addressed is whether the amount and type of dietary fat affects esterases in plasma. Rats were fed semipurified diets containing 2.0 to 19.4% (w/w) of fat in the form of coconut fat or corn oil. Fat was added to the diets at the expense of isocaloric amounts of carbohydrates. Plasma total esterase activities measured with 4-nitrophenylacetate as substrate were slightly increased with increasing fat intakes. However, an increase in fat concentration of the diet was associated with a pronounced increase in the activity of the so-called ES-1 isozyme in plasma. ES-1, which represents very little plasma total esterase activity, was quantified densitometrically as the high-mobility, anodal esterase band on polyacrylamide gel electrophoresis. The positive association between amount of dietary fat and ES-1 activity was identical for coconut fat and corn oil.

Animals↗
PubMed2000

Purification and characterization of a thermostable esterase from the moderate thermophile Bacillus circulans.

The thermostable esterase from the moderate thermophile Bacillus circulans was purified to homogeneity using a four-step procedure. Esterase activity was associated with a protein of molecular mass 95 kDa, composed of three identical subunits of 30 kDa. The esterase activity was thermostable with a maximum activity at 55 degrees C using initial rate assay. The half-inactivation temperature was 71 degrees C after a 1-h treatment, which compared favorably to that of other enzymes. Activity at temperatures of 30-37 degrees C was high (about half of maximum), making this new enzyme very attractive for applications in this moderate temperature range. The esterase also showed high activity at a rather alkaline pH (higher than 10). The specificity pattern showed a marked specificity for mid-chain-length fatty acids (3-8 carbon atoms), which classified the enzyme as a carboxylesterase.

Bacillus↗
PubMed1991

Spectrophotometric assay and electrophoretic detection of trans-feruloyl esterase activity.

Wheat bran cell walls were subjected to mild acid hydrolysis and the major phenolic product was purified and identified as 5-O-(trans-feruloyl)-arabinofuranose. Sensitive continuous and stopped, microtiter plate-based spectrophotometric assays for trans-feruloyl esterase activity were developed using this compound as substrate. Procedures were also developed for the detection of trans-feruloyl esterase activities on gels following electrophoresis using this compound. These procedures are applicable to other natural feruloyl esters derived from plant cell walls by enzymatic hydrolysis. The extracellular trans-feruloyl esterases of Aspergillus niger 814 grown on 1% wheat bran were fractionated by anion-exchange chromatography and isoelectric focusing. These studies indicate that there are multiple forms of trans-feruloyl esterase but that most activity is associated with a major isozyme with a pI of 3.2.

Arabinose↗
PubMed1979

Purification and properties of human serum esterase.

Human serum esterase was purified by affinity column chromatography on a column of covalently linked p-trimethylammoniumanilinium dichloride to Sepharose 4B. The purified preparation hydrolysed both benzoylcholine and tributyrin. p-Trimethylammoniumanilinium dichloride inhibited non-competitively the hydrolysis of tributyrin and inhibited competitively the splitting of benzoylcholine. The Km value was 0.62 . 10(-3) M for tributyrin and 0.4 . 10(-3) M for benzoylcholine. Antiserum to this purified esterase was prepared in rabbit and it was found that the antiserum did not inhibit esterase activities of human liver, muscle and adipose tissue, although it could inhibit completely the esterase activities of human serum.

Benzoylcholine↗
PubMed1978

Partial purification and properties of monoacylglycerol lipase and two esterases from isolated rat small intestinal epithelial cells.

In intestinal epithelial cells, three enzymes possessing monoacylglycerol hydrolase activity were found and partially purified. Two of these enzymes have properties that justify their classification as an esterase and one as a monoacylglycerol lipase. The three enzymes show similar Km values for monooleoylglycerol and each shows similar activity towards 1- and 2-monopalmitoylglycerol. Antiserum raised in rabbits against rat liver monoacylglycerol lipase inhibits the intestinal lipase completely, suggesting that the enzymes are at least partially similar. The esterases of small intestinal villus cells were not inhibited by the antiserum against liver monoacylglycerol lipase. It was calculated that the esterases account for approx. 2/3 of the monooleoylglycerol hydrolase activity in epithelial cells. Monoacylglycerol lipase also hydrolyzed palmitoyl-CoA, while the esterases did not. The enzymes were inhibited by micellar palmitoyl-CoA. The hypothesis that palmitoyl-CoA is an important regulator for monoacylglycerol acylation is discussed in the light of these new findings.

Acylation↗
PubMed1985

Purification and properties of arginine esterases from Bitis arietans (puff adder) venom.

An arginine esterase (FT1) was purified from B. arietans venom by gel-filtration and ion-exchange chromatography. The purified enzyme contains 21.6% of carbohydrate, 240 amino acids including 12 half-cystine residues and has a mol. wt of approximately 43,000. The purified enzyme has a high esterolytic activity towards N-alpha-benzoyl-L-arginine ethyl ester but shows no proteolytic activity against Azocoll and no clotting activity with fibrinogen. The N-terminal sequence of the arginine esterase from B. arietans venom shares a significant degree of sequence homology with the arginine esterase of B. nasicornis, the thrombin-like enzyme of C. adamanteus and the kallikrein-like enzymes of C. atrox venoms. It would appear that the arginine esterase from B. arietans venom exists in various multiple forms of the enzyme.

Amino Acid Sequence↗
PubMed1986

Proteolytic activity of arginine esterase from dog seminal plasma towards actin and other structural proteins. Comparison with trypsin and kallikrein.

At equimolar ratio of enzyme/substrate, actin, tropomyosin, fibronectin and myosin were extensively hydrolyzed during an incubation of one hour at 37 degrees C. Dog serum albumin, ovalbumin, bovine gamma-globulin and human prostatic acid phosphatase were not hydrolyzed. The activity of arginine esterase towards actin at pHs 6.5, 7.1 and 7.6 was respectively 60, 74 and 84% of the one found at optimum pH 8.2. The cleavage products of actin by arginine esterase and trypsin were similar although trypsin activity was 5000-fold higher. Kallikrein produced a major fragment of actin not observed with arginine esterase and trypsin. It is concluded that arginine esterase has a low trypsin-like activity towards structural proteins and that this activity may have a physiological significance.

Actins↗
PubMed1984

Neurotoxic esterase: gel filtration and isoelectric focusing of carboxylesterases solubilized from hen brain.

Carboxylesterase activity (EC 3.1.1.1) of hen brain including neurotoxic esterases NTEA and NTEB is solubilized from lyophilized lipid-extracted brain material by the use of n-octylglucoside. The solubilized enzymes are subjected to free isoelectric focusing, six carboxyl - esterase activity peaks are obtained. By gel filtration on Sephacryl S-300 neurotoxic esterases are separated from carboxylesterase isoenzymes V and X. The molecular weight of the neurotoxic esterases is estimated to be 1.8 X 10(6).

Animals↗
PubMed1988

Electrophoretic data in designing strategies for purification and identification of a highly polymorphic bacterial esterase.

We have purified a bacterial enzyme, designated esterase M, by tailoring an efficient and rapid strategy with information derived from titration curves of proteins in crude extract. The pH-dependent stability of the enzyme activity observed by titration pattern allowed an acidic pH treatment of extract and a cationic exchange chromatography at pH 4.1. These two steps were followed by an anionic exchange chromatography and a preparative electrophoresis. Thus, the enzyme was purified about 2000-fold within two days with a recovery of 13.3%. The electrophoretic variants of esterase M were investigated for their molecular relationship through the specific effect of antibodies on esterase electrophoretic pattern (immunosubtractive electrophoresis) which is applicable to large series of samples. By this process, we have demonstrated the presence of common antigenic determinants among the electromorphs of esterase M produced by the three species of motile Aeromonas.

Aeromonas↗
PubMed1989

Interleukin 1 induction of a serine esterase in a murine T cell line is inhibited by fetal calf serum.

In PC60 cells a serine esterase associated with the cytotoxic granules (BLT-esterase) is induced by interleukin 1 (IL-1). The induction was markedly reduced by fetal calf serum (FCS). A defined culture medium was therefore developed in which the PC60 cells proliferated equally well as in serum-containing medium. In this new medium, IL-1 induced BLT-esterase to much higher levels of activity than in serum-containing medium. When testing IL-1 induction of BLT-esterase with various batches of FCS, no correlation was found between cell proliferation and the responses to IL-1. It was concluded that FCS contains one (or several) inhibitor(s) of IL-1 action.

Animals↗
PubMed1988

Androgen regulation of canine prostatic arginine esterase mRNA using cloned cDNA.

Canine prostatic arginine esterase complementary DNA has been cloned in pPBS27, a new cloning vector. The relative abundance of androgen-regulated mRNA in intact dog prostate was reflected by the finding that a high proportion of the clones in the cDNA library hybridized strongly by plaque or colony hybridization with a poly(A)+ RNA probe from intact dog prostate but not with a poly(A)+ RNA probe from castrated dog prostate. One clone carrying a 400 base pairs cDNA insert was selected for further studies. Translation of the hybrid-selected RNA in a cell-free system resulted in the production of a 31 kDa peptide immunoprecipitable by antibodies against arginine esterase. This identification was confirmed by partial sequence analysis of the cDNA revealing an encoding protein with high homology to known kallikreins. Northern blot analysis of poly(A)+ and total RNA showed that arginine esterase mRNA had an approximate size of 1.0 kb which corresponded to a major androgen-regulated RNA species that could be observed after denaturing agarose gel electrophoresis of prostatic poly(A)+ RNA from intact dogs. Dot-blot analysis showed that dogs which had been castrated 3 weeks before had more than 100-fold lower arginine esterase mRNA level than intact dogs or castrated dogs treated with Depo-testosterone.

Amino Acid Sequence↗
PubMed1985

Enzymatic characterization of arginine esterase from dog seminal plasma.

Previously purified arginine esterase from dog seminal plasma was characterized enzymatically. The enzyme was found to have a rather narrow specificity for arginine esters, much less for lysine esters and was practically devoid of activity towards tyrosine esters, casein, albumin and azocoll. It had a broad optimum pH between 8 and 9. It presented no kallikrein-like activities either in the blood pressure test in dog or in the rat uterus contraction test. It was inhibited by bovine pancreas trypsin inhibitor, aprotinin, phenylalanylprolyl arginine chloromethyl ketone, diisopropylfluorophosphate, phenylmethylsulfonyl fluoride, sodium dodecyl sulfate and leupeptin, but not by soybean trypsin inhibitor, tosyllysine chloromethyl ketone, tosylamide-2-phenylethyl chloromethyl ketone, iodoacetamide, Triton X-100 and EDTA. Experiments involving incubation of prostatic cytosol with purified arginine esterase showed that actin was the only important prostatic protein that was extensively hydrolyzed by this enzyme. It is not known presently whether the hydrolysis of actin is related to a true physiological function of the enzyme and whether actin and arginine esterase ever come into contact with each other in vivo. These properties indicate that arginine esterase from dog seminal plasma is different from other known proteinases including classical kallikreins, although it presents many similarities with this class of enzyme.

Animals↗
PubMed1985

The separation of sheep and human serum "A"-esterase activity into the lipoprotein fraction by ultracentrifugation.

Using sheep and human serum the relationship between centrifugation time and yield of total lipoprotein, HDL-cholesterol and "A"-esterase in lipoprotein was studied employing different centrifuge rotors. More rapid separation of these components was obtained with a vertical rotor than with an angled rotor. The procedures commonly employed for lipoprotein separation gave low yields of lipoprotein "A"-esterase and HDL-cholesterol. The separation of sheep serum "A"-esterase into the lipoprotein fraction was not in phase with that of HDL-cholesterol and the pattern of separation was different from that in human serum. These results provide further evidence that serum "A"-esterase activity is associated with different species of HDL-particle.

Animals↗
PubMed1986

Multiple forms of juvenile hormone esterase active sites in the hemolymph of larvae of Trichoplusia ni.

Kinetic analysis was performed on the juvenile hormone (JH) esterase activity in the hemolymph of feeding, last instar larvae of Trichoplusia ni (Lepidoptera: Noctuidae). When the results were analyzed by several different graphical and regression procedures, all approaches yielded the same conclusion that at least two forms of JH esterase active sites exist in the hemolymph. The apparent Km for one site for JH I, II and III was 8.5 X 10(-8) M, and 6.6 X 10(-8) M, respectively. The Km for the other site for JH I, II and III was 6.6 X 10(-7) M, 7.6 X 10(-7) M, 40 X 10(-7) M, respectively. When hemolymph JHE activity was subjected to high resolution isoelectric focusing (IEF), two distinct large peaks of JHE activity were observed, with pIs of 5.3 and 5.5, as well as a small peak at pI 5.1. Separate kinetic analysis of the JHE activity in each peak showed that only the higher Km active site for each substrate was present (in the 10(-7) M range). These data necessitate a change in the current model for JHE in T. ni, and some other insects, which states that a single active site is responsible for most or all of the JH esterase activity in vivo. The data also explain the different estimates of the Km of JHE in T. ni obtained by different laboratories. Studies on the purification of, and the development of inhibitors for, JHE esterase must consider the role of both JHE forms and sites in regulation of T. ni metamorphosis.

Animals↗