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At least 1,783 records · Page 99Linked to original sources
PubMed1992

[A new esterase locus, Es-19, in the rat].

A new esterase polymorphism was identified in epididymal homogenates from inbred rat strains by polyacrylamide gel electrophoresis. The inbred rat strains showed either fast (A) or slow (B) bands. Strain distributions of the phenotypes differed from those of other esterase loci. Genetic analyses revealed that the polymorphism is controlled by codominant alleles (Es-19a and Es-19b) and is not linked to linkage groups, I, II, IV, V, VI, XIII of the rat.

Alleles↗
PubMed2005

Evidence for a natural hybrid of peacock bass (Cichla monoculus vs Cichla temensis) based on esterase electrophoretic patterns.

Esterase (Est) and esterase-D (Est-D) electrophoretic patterns identified by starch gel electrophoresis of skeletal muscle protein extracts of 184 specimens of three species of peacock bass, locally known as tucunares (Cichla monoculus, C. temensis and Cichla sp), plus four specimens of a supposed hybrid (C. monoculus vs C. temensis), collected from the Central Amazon, were examined to determine if they could aid in identifying a supposed hybrid between C. monoculus and C. temensis. Six zones of electrophoretic activity were found with these enzyme systems. The Est enzyme showed one zone of activity, formed by bands 1, 2 and 3, plus three zones of activity, presumably controlled by Est-1, 2 and 3 loci. The Est-D enzyme had two zones of activity, presumably controlled by Est-D1 and Est-D2 loci. Cichla monoculus and C. temensis shared band 2 and alleles Est-1(1), Est-2(1), Est-3(2), and Est-D1(1), and therefore these were useless for identifying hybrids between the two species. However, a probable hybrid pattern of bands 1, 2, and 3, presumably generated by a combination of pattern 12 from C. monoculus with pattern 23 from C. temensis, resulting from a possible cross between these two species, was detected. Although the Est-D2 locus cannot be considered an ideal diagnostic marker for identifying the supposed hybrid (C. monoculus vs C. temensis), as it is polymorphic, it proved to be useful for determining the origin of the hybrid, i.e., which parental species were involved in the hybridization process.

Animals↗
PubMed2005

[Some enzymes associated with lipid catabolism in the Fasciola hepatica larvae--Galba truncatula system. I. Esterases and lipases].

Histochemical and cytofotometric techniques were used to detect esterase and lipase in the hepatopancreas of the snail Lymnaea truncatula and in larval stages of its parasite Fasciola hepatica. Activities of both enzymes were shown to increase in the infected hepatopancreas, compared with the control. The effect is ascribed by the authors to compensation processes emerging as a defence mechanism in the snail. Both enzymes, esterase and lipase proved to be highly active in tissues of sporocysts, rediae and cercariae, thus demonstrating the larvae to be capable of katabolism of lipids and utilising them as an energy source.

Animals↗
PubMed1995

Changes in serum lipid profile and esterases of rats after sublethal daily doses of dimethoate.

Male Wistar rats were injected by dimethoate (10 mg/0.5 ml) daily for 8 successive days. Controls received the same amount of saline., A group of 5 rats were anesthetized at 0, 2, 4, 6 and 8 days of injection. Blood was withdrawn from heart. serum lipid components and 4 species of serum esterases were assayed for each group. A general decrease in the activities of serum esterases was observed. A marked decrease also was observed in lipids profile during the 8 days course of experiment.

Acetylcholinesterase↗
PubMed1991

Single incubation double esterase cytochemical reaction using a single coupling reagent.

Most methods used in double esterase cytochemistry for the diagnosis and classification of acute myeloid leukaemias require double incubation and staining, using separate coupling reagents. We evaluated a method by Swirsky on our normal and abnormal blood and bone marrow smears where only a single incubation and the use of a single coupling reagent is required. Its short incubation period and its strong positive reaction for butyrate esterase in demonstrating cells of monocytic lineage gives it an advantage over the conventional double incubation technique.

Esterases↗
PubMed1991

[Leukocyte esterase in the rapid detection of intraamniotic infection].

Several lines of evidence support the view that premature rupture of the membranes and premature labor are associated with bacterial infection of the amniotic cavity. The standard method of diagnosing intraamniotic infection is amniotic fluid culture, but the results become available only after 72 hours. Methods for more rapid diagnosis of bacterial invasion are therefor needed. We examined leukocyte esterase activity for this purpose. Amniotic fluid obtained from 62 women in preterm labor was cultured for aerobic, anaerobic and mycoplasma species. Leukocyte esterase activity was measured with a Bio-dynamics test strip. The sensitivity of the test was 50.0% and its specificity 93.4%. It was found to be a simple and rapid method for the detection of intraamniotic infection.

Amniotic Fluid↗
PubMed1991

Triggering of CD8+ cytotoxic T lymphocytes via CD3-epsilon differs from triggering via alpha/beta T cell receptor. CD3-epsilon-induced cytotoxicity occurs in the absence of protein kinase C and does not result in exocytosis of serine esterases.

The requirement for protein kinase C (PKC) during triggering of murine CD8+ CTL was investigated. To this, CTL were depleted for PKC by pretreatment with PMA. This procedure neither influenced alpha/beta-TCR, CD3-epsilon, CD8, CD2, and lymphocyte function-associated Ag-1 expression, nor CTL-target cell conjugate formation. Although cytolytic effector function of PKC-depleted CTL triggered via alpha/beta-TCR structures was completely inhibited, target cell lysis induced via CD3-epsilon remained unaffected. Furthermore this PKC-independent cytolysis pathway was not associated with the release of serine esterases. Analyses at the clonal level revealed that PKC depletion blocked the cytolytic response of up to 95% of alpha/beta-TCR triggered CTL clones. The data suggest the existence of a distinct signaling pathway triggered via CD3-epsilon that is not associated with exocytosis of serine esterases and probably independent of PKC.

Animals↗
PubMed1976

Cholesterol esterase activity in body fluids.

Antistreptolysin O activity (greater than or equal to 200 Todd units/ml) was found in 20% of 25 ascitic fluids, 20% of 55 pleural fluids and 37-5% of 56 joint fluids. These levels are not due to antibody but to the cholesterol moiety of altered beta-lipoproteins. The activity is precipitable with 10% dextran sulphate. Incubation of mixtures of fluids with titres less than 200 and normal human serum generated eight-fold or greater rises in antistreptolysin titres. This results from the activity of cholesterol esterase in the fluid acting on the beta-lipoprotein of the serum and activity was noted in 90% of ascitic fluids, 59% of pleural fluids and 54% of joint fluids. However, mixtures showing no such rise probably also contain esterase, the failure to demonstrate antistreptolysin activity being due to equilibration of ester derived cholesterol with sub-fractions of high density and very low density lipoproteins.

Antistreptolysin↗
PubMed1990

Granulated metrial gland cells of pregnant mouse uterus are natural killer-like cells that contain perforin and serine esterases.

The mouse uterus during pregnancy contains a large population of lymphoid cells termed granulated metrial gland (GMG) cells. Our observations suggest that these cells are highly activated cytolytic lymphocytes related to NK or lymphokine-activated killer cells. Immunostaining demonstrated asialo GM1 and Thy-1 on GMG cells, both of which are expressed by NK cells. Decidua basalis tissue and isolated GMG cells contained three proteins that are characteristic of activated cytolytic lymphocyte granules: perforin, serine esterase 1, and serine esterase 2. These mediators were demonstrated in GMG cells by Western blot analysis using polyclonal antisera and by Northern blot analysis using specific cDNA probes for their mRNA. The proteins were not detected in normal spleen or liver or in asialo GM1+ cells isolated from those organs, consistent with the absence of these mediators from resting cytolytic cells. The amount of perforin in GMG cells was similar to that present in cloned, IL-2-stimulated, CTL shown previously to contain a large amount of this protein. A large population of NK cells bearing the surface marker LGL-1 was demonstrated at the implantation site by labeling with monoclonal antibody 4D11, but T cells were not detected. Many LGL-1+ cells at the implantation site expressed the GMG cell markers asialo GM1, Thy-1, and perforin. Staining intensities were inversely correlated, with LGL-1-bright cells showing little or no staining of GMG cell markers and LGL-1-faint cells showing more obvious staining of GMG cell markers. This suggests that LGL-1+ NK cells may differentiate in situ to GMG cells, losing LGL-1 and gaining a high concentration of GMG cell markers in the process. Activated cytolytic cells related to NK or lymphokine-activated killer cells may function in the pregnant rodent uterus to intercept and kill aberrant placental or embryonic cells that might otherwise enter the female and proliferate.

Animals↗
PubMed1977

Human leukocyte migration inhibitory factor (LIF). IV. 3',5'-cGMP protects LIF against inactivation by the esterase inhibitor phenylmethylsulfonyl fluoride.

Recently reported experiments suggest that human leukocyte migration inhibitory factor (LIF) has properties of an esterase and a protease with substrate specificities directed against arginine esters and amides. Also reported previously, the synthetic phosphodiester bis-p-nitrophenyl phosphate (BNPP) but not various phosphomonoesters preserve LIF activity in the presence of the serine esterase inhibitor phenylmethylsulfonyl fluoride (PMSF). In this paper I demonstrate that guanosine 3'5'-cyclic monophosphoric acid (3',5'-cGMP), a naturally occurring phosphodiester, at concentrations in excess of 10(-5)M also protects LIF against PMSF inactivation. The effect seems specific for the diester bond, its position in the nucleotide, and the guanine base. The possibility that LIF may be a multifunctional or an allosteric enzyme regulated by 3',5'-cGMP is discussed.

Cyclic AMP↗
PubMed1978

On the distributive patterns of phosphatases and non-specific esterase and their functional aspects amongst the constituents of the photoreceptors of the Indian Medicinal leech, Poecilobdella granulosa (Savigny, 1822).

In the present contribution the distributive pattern of phosphatases and non-specific esterase amongst the constituents of the leech eye has been revealed and the significance of the enzymatic locales in relation to the visual processes has been discussed. All the phosphatases studied demonstrate absence of the activity in the lens. Activity of the phosphatases, however, is restricted to the plasma membrane and associated cytoplasm to varying degrees. The significance of the phosphatases in the nerve impulses and transmission has been highlightened. The observation of considerable significance relates the demonstration of a high degree of non-specific esterase activity in the lens, which has defied all the phosphatases. Another observation relates to the positive activity of 5-nucleotidase in the group of axons constituting optic nerve. The significance of this observation has also been discussed.

Acid Phosphatase↗
PubMed1979

The hydrolysis of cholesterol esters in plasma lipoproteins by hormone-sensitive cholesterol esterase from adipose tissue.

Adipose tissue contains a high level of neutral esterase active against emulsions of cholesteryl oleate. The present studies show that this enzyme can also effectively hydrolyze the cholesterol esters in native rat plasma high density lipoproteins (HDL) and low density lipoproteins (LDL). The hydrolysis of lipoprotein cholesterol esters by a pH 5.2 isoelectric precipitate fraction from the freshly prepared 100,000 X g supernatant of chicken adipose tissue was low, but increased more than 50-fold on activation with cyclic AMP-dependent protein kinase. Rat adipose tissue homogenates were also very active against lipoprotein cholesterol esters, hydrolyzing as much as 60% of the total labeled cholesterol ester in HDL or LDL in 1 h. Activity was optimal at pH 7 and very low at pH 4. No protease activity was detected at pH 7 and, since assays were done in 2 mM EDTA, phospholipase A activity was presumably negligible. The results show that hormone-sensitive cholesterol esterase of adipose tissue has ready access to the neutral lipid core of plasma lipoproteins, either because the enzyme penetrates the polar shell or because the cholesterol ester in the core is exposed, at least intermittently, to allow enzyme-substrate complex formation. Whether or not this enzyme activity plays a role in lipoprotein degradation by adipose tissue remains to be determined.

Adipose Tissue↗
PubMed1990

In vitro modifications of rat NTE and other esterases by chemicals which induce delayed neurotoxicity in vivo.

A rat in vitro model has been developed which permits direct study of the biochemical mechanisms involved in delayed neurotoxicity induced by any chemical compound, not only organophosphates. Using rat brain homogenate, a parallel study on the activity of neurotoxic esterase (NTE) and total esterases (TE) compared the action of metamidophos, which is known to induce delayed neurotoxicity, and the synthetic fatty acid anilides, oleylanilide and linoleylanilide. Inhibition in the activity of NTE and TE, unrelated to the concentration and the incubation time assayed, was caused by metamidophos, while the anilides showed a 2-phase concentration-time dependent behaviour. This confirmed the results we previously obtained in vivo. In both cases the appearance of delayed neuropathy was related to modification of NTE activity. We concluded that phosphorylation of the enzyme may not be the only biochemical requirement for the development of delayed neurotoxicity syndromes in which modification of NTE is produced.

Anilides↗
PubMed1990

Histochemical characterization of esterases from three species of amphistomes.

Esterase activity of Gigantocotyle explanatum, Ceylonocotyle scoliocoelium and Cotylophoron cotylophorum were localized histochemically in various regions associated with nutrition, viz, integument, pharynx, sucker and gastrodermis. The intensity of the reactions varied in the different regions of the same parasite and also from species to species. The distribution and relative activity of the esterases were investigated and the results reveal that the influence of inhibitors/activators on enzyme activity varied in the different regions. Based on the inhibitory effects it is inferred that carboxylesterases are distributed in the region of the integument, pharynx and gastrodermis, acetylesterases in the suckers and cholinesterase in the subtegumental cells and muscle of these three trematodes.

Animals↗
PubMed1975

Cationic proteins of human granulocytes. IV. Esterase activity.

The purfied antibacterial cationic proteins 1 to 7 (component 1 being the most cationic) of human neutrophil granulocytes have been assayed for enzyme activities. Components 1 to 4 and component 7 exhibited activities on tyrosine esters indicating a chymotrypsin-like activity with a neutral pH optimum. The inhibition of the esterase activity by diisopropyl fluorophosphate and phenylmethyl sulfonylfuoride also indicated the similarity to chymotrypsin, with a serine residue in the active center. In addition, the cationic proteins attacked complex substrates like casein and fibrinogen, suggesting a true proteolytic activity. Since the esterase activity of these proteins is heat-labile but the antibacterial activity against Staphylococcus aureus is heat-stable, it is concluded that the chymotrypsin-like activity is not essential for the microbicidal activity. There is evidence to suggest that the cationic proteins of human granulocytes are present in the cytoplasmic granules and exhibit antibacterial activity after release to the phagocytic vacuole and that, after extrusion from the cell, the proteins might be involved in the mediation of the inflammatory process due to enzyme and cationic activities.

Arginine↗
PubMed1975

Kinetic studies of carboxypeptidase Y. II. Effects of substrate and product analogs on peptidase and esterase activities.

Reversible inhibition of the peptidase and esterase activities of CPase Y [EC 3.4.12.1] was investigated with substrate and product analogs known to be inhibitors or effectors of pancreatic carboxypeptidases A or B [EC 3.4.12.2 or 3]. L-Amino acids and NH2-blocked L-Amino acids showed competitive-type inhibition, whereas their D-enantiomers caused less inhibition than the L-enantiomers, and showed non-competitive or mixed-type inhibition. Some phenylalanine analogs, e.g. beta-phenylpropionic acid and t-cinnamic acid, were also reversible inhibitors of CPase Y. The type of these inhibitors and their K1 values were generally parallel for both the peptidase and esterase activities.

Amino Acids↗
PubMed1989

Demonstration of the increase in serine esterase-positive T cells in hairy-cell leukemia patients undergoing alpha-interferon therapy.

An increased number of serine esterase non-B lymphocytes including CD4+ helper/cytotoxic cells were observed in hairy-cell leukemia patients during (56 +/- 18) and immediately post (52 +/- 16) alpha-interferon therapy compared with pretreatment status (17 +/- 5) and normal donors (29 +/- 3). This increase in lymphocytes bearing one of the putative cytotoxicity-linked proteins was paralleled by a higher cytotoxicity towards K562 cells in the NK and LDCC assays during therapy and similarly, but to a much reduced level, against the hairy-cell derived JOK-1 target cells. Phenotypically, a higher percentage of non-B cells also expressing DR or CD11 antigens were seen in the HCL patients during IFN therapy. In lymphocyte target binding assays, a high affinity of effector to target conjugate formation was observed when either of the hairy cell lines JOK-1 or Hair-M was chosen as targets for IFN-therapy effector cells. Although predominantly CD4+ cells exhibited the in vitro affinity for effector/target conjugation with autologous HCs, the polarisation of serine esterase activity towards the E/T membrane contact area was shown by both CD4+ and CD8+ cells during a short incubation period and before target cell death.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

Isolation, properties, and the complete amino acid sequence of a second form of 60-kDa glycoprotein esterase. Orientation of the 60-kDa proteins in the microsomal membrane.

A second form (form 2) of glycosylated esterase was isolated from liver microsomal membranes and characterized. The subunit molecular weight of form 2 is identical to that of the 60-kDa protein previously reported (Ozols, J. (1987) J. Biol. Chem. 262, 15316-15321). The NH2 terminus of the form 2 enzyme is blocked. Digestion of form 2 with pyroglutamyl aminopeptidase, followed by electroblotting and sequence analysis of the blotted protein, indicated that a pyroglutamyl residue was located at the NH2 terminus. Sequence analysis of the deblocked protein as well as characterization of the peptides obtained from enzymatic and chemical cleavages of the intact protein led to the elucidation of its complete amino acid sequence. The protein is a single polypeptide consisting of 532 residues. Carbohydrate is attached at asparaginyl residue 249. The sequence of form 2 esterase is 50% identical to the sequence of form 1 enzyme. The amino acid sequence of the first 26 residues of form 1 enzyme from human liver microsomes shows that 23 residues are identical to that of rabbit form 1, but only 8 residues that are identical to form 2. Treatment of the forms 1 and 2 isozymes with N-glycosidase F or endo-N-acetylglucosaminidase H resulted in a decrease of their subunit molecular weights, indicating that the carbohydrate attached is of the high mannose type. To determine whether the 60-kDa proteins are located on the cytoplasmic or luminal side of the endoplasmic membrane, microsomes were treated with proteolytic enzymes and the two 60-kDa isozymes were isolated and characterized. Sequence analysis of both proteins indicated that their NH2 termini were unaffected by proteolysis. Form 1 isozyme isolated from trypsin-treated microsomes, however, lacked the COOH-terminal heptapeptide (residues 533-539). These results, in addition to the finding of an N-linked carbohydrate, suggest that the two 60-kDa proteins are oriented on the luminal side of the endoplasmic membrane.

Amino Acid Sequence↗