Current problems on the structure and classification of mammalian liver carboxylesterases (EC 3.1.1.1)

Junge, Wolfgang; Krisch, K

doi:10.1007/bf01659937

Cited by 42 publications

(19 citation statements)

References 39 publications

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“…Similar enzymes have been isolated from pig kidney [35,36] bovine liver [35,37 -391, human liver [40], rat liver [41] and some other mammalian organs [4]. The subunit weight of these enzymes are consistently in the range from 55000 to 63000 [42]. It is interesting to note that this corresponds to the value reported here for the amidase/esterase from P. acidovorans AE 1 as well.…”

Section: Discussionsupporting

confidence: 80%

“…However, the bacterial enzyme does not associate but exists as a stable monomer, at least under the conditions reported here. The amino acid composition of the bacterial enzyme is quite similar to that of the mammalian carboxylesterases but differs from pig liver esterase by more than 20% in the contents of alanine, glycine and arginine [42].…”

Section: Discussionmentioning

confidence: 82%

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Characterization of an Inducible Amidase from Pseudomonas acidovorans AE 1

1975

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The main molecular and catalytic properties of an acetanilide‐hydrolyzing enzyme from Pseudomonas acidovorans AE 1, purified to a homogeneous state, were investigated. The molecular weight was 57500 as determined by gel filtration and 55300 as computed from the amino acid composition. By polyacrylamide gel electrophoresis in dodecylsulfate a polypeptide chain weight of 56700 was obtained. Based on the reaction of the highly purified enzyme with diethyl‐4‐nitrophenyl phosphate an equivalent weight of approximately 59100 was found. From these results it was concluded that the enzyme consists of a single polypeptide chain and contains one active site per molecule. The enzyme hydrolyzed esters as well as certain aromatic amides. It also catalysed the transfer of acetyl groups to phenetidine yielding phenacetin. The activities towards aliphatic esters were much smaller. The enzyme was stable at pH values ranging from 7 to 9 and its pH‐optimum was about 10. It was strongly inhibited by organophosphorous compounds, like diethyl‐4‐nitrophenyl phosphate or diisopropylphosphorofluoridate, as well as by physostigmine sulfate and ‐SH‐blocking reagents, like HgCl2 or 4‐chloromercuribenzoic acid. o‐Nitrophenol caused a competitive inhibition and phenetidine an uncompetitive inhibition.

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Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 82%

Characterization of an Inducible Amidase from Pseudomonas acidovorans AE 1

1975

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“…On isoelectric focusing, highly purified pig liver esterase was separated into five main pcaks. Studies on the substrate specificities of these main variants with methyl butyrate, o-nitroacetanilide and butyrylcholine showed that all the enzyme forms hydrolyzed all three compounds, but that the ratios of the activities differed considerably [17]. They concluded that the main forms of these esterase isoenzymes were y y y , ayy, awl and aaa trimers.…”

Section: Discussionmentioning

confidence: 99%

Carboxylesterases in Rat and Human Sera and Their Relationship to Serum Aryl Acylamidases and Cholinesterases

Tsujita

Okuda

1983

European Journal of Biochemistry

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The three enzyme activities, carboxylesterase, aryl acylamidase and cholinesterase activities, have been found in rat and human sera. Rat serum carboxylesterase associated with serum aryl acylamidase activity, but not with serum cholinesterase activity, was purified by ammonium sulfate precipitation, followed by successive chromatographies on DEAE-cellulose, blue Sepharose and QAE-Sephadex, and then electrophoresis. Evidence for the identity of the two enzymes, carboxylesterase and aryl acylamidase, was their co-elution profiles and co-purification in the different steps, including electrophoresis, with constant ratios of specific activities and percentage recoveries.Human serum carboxylesterase associated with serum cholinesterase, purified earlier, was compared with the rat serum esterase. Human serum carboxylesterase and aryl acylamidase activities were inhibited by serotonin and neostigmine, whereas rat serum carboxylesterase and aryl acylamidase activities were not affected by these compounds. Tyramine activated human but not rat aryl acylamidase. Rat and human serum esterase activities were both strongly inhibited by the diisopropylfluorophosphate. Both esterases catalyzed the hydrolysis of short-chain triacylglycerols, such as tributyrin, and medium-chain monoacylglycerols, such as monocaprin, but not the hydrolysis of long-chain triacylglycerols.Carboxylesterases are widely distributed in animals and plants [I]. In mammals, their highest activities are found in the serum, liver, kidney and intestinal mucosa. Despite the wide distribution of this enzyme, most of its known substrates are foreign compounds that are not normally involved in intermediary metabolism. Thus the physiological function of carboxylesterase is still obscure.We previously reported purification of human serum carboxylesterase by affinity chromatography and suggested that this enzyme was associated with serum cholinesterase [2, 31. Evidence for the association of the two activities in human serum included their co-elution profiles, co-purification at different steps with constant ratios of specific activities and percentage recoveries and co-precipitation by antibody raised against the purified enzyme. Recently, George and Balasubramanian [4] reported that human serum aryl acylamidase was associated with serum cholinesterase. From these findings, it is predicted that human serum carboxylesterase is associated with serum aryl acylamidase and cholinesterase.It was, therefore, of interest to examine the metabolic function of carboxylesterase and to determine whether serum carboxylesterase is generally associated with aryl acylamidase and cholinesterase from different sources. In the present work we purified the carboxylesterase of rat serum and showed that it was associated with serum aryl acylamidase. We also compared the properties of rat serum carboxylesterase with human serum carboxylesterase associated with aryl acylamidase and cholinesterase.Abbreviation. SDS, sodium dodecylsulfate. Enzymes. Carboxylesterase or non-specific esterase...

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“…Hydrolase activity has already been demonstrated in serum and liver, kidney, muscle and cerebral tissues and it is currently well established that such hydrolysis enzymes act on different chemical species such as glucosides, starches and aldehydes, endogenous and exogenous e-stems [1][2][3][4][5][6][7][8]. In the nervous tissue, hydrolysis-esterase activity exists in isoenzymic forms, for example 3 and 5 acetyl and aryl esterase, respectively [6].…”

Section: Introductionmentioning

confidence: 99%

“…Chemically, heroin is a diacetylmorphine, characterized by the presence of two ester groups and therefore susceptible to hydrolysis to morphine by esterase enzymes. Therefore, it has been suggested that in vivo metabolism of heroin depends on the action of cholinesterase that seems to have partial affinity for such substrate, or of various aryl esterases already demonstrated to be present in the rat brain [6][7][8][9]. Based on this suggestion, and to define an eventual distribution specificity of such type enzymes active on heroin, the spinal cord and the remaining five large regions of the rat brain were prepared i.e., telencephalon, mesencephalon, diencephalon, cerebellum and medulla oblongata.…”

Section: Introductionmentioning

confidence: 99%

Titrimetric and parallel voltammetric sensitivity to heroin metabolism in brain

Crespi¹

2017

Brain Nerves

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A titrimetric technique has been successfully employed to measure esterase activities in different tissues. We have applied this tech nique to investigate the distribution of the esterase enzymes in spinal cord and five different brain areas of the rat (telencephalon, mesencephalon, diencephalon, cerebellum and medulla oblongata). The presence of non-specific esterase activity has been determined using alpha-napthyl acetate, a widely employed substrate for these en zymes, whereby the possible existence of "heroin-esterases" has been tested. Our results suggest that the activity of cerebral esterase's on heroin can be studied selectively at pH 8.5, showing quantitative differences in the distribution of these so-called " heroin-es terases" in spinal cord and in the five brain areas studied.In parallel, the efficacy of such "heroin-esterases" has been verified using voltammetric analysis of the influence of the brain enzymes upon the substrate heroin resulting in the evidence of an oxidation signal due to the selective oxidation of uprising morphine.Furthermore, the localization of these enzymes seems to overlap the distribution of brain morphine receptors, suggesting a possible role for these "heroin-esterase" in the metabolism and subsequent ly in the pharmacological activity of heroin, i.e., by converting this drug into morphine.

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Current problems on the structure and classification of mammalian liver carboxylesterases (EC 3.1.1.1)

Cited by 42 publications

References 39 publications

Characterization of an Inducible Amidase from Pseudomonas acidovorans AE 1

Characterization of an Inducible Amidase from Pseudomonas acidovorans AE 1

Carboxylesterases in Rat and Human Sera and Their Relationship to Serum Aryl Acylamidases and Cholinesterases

Titrimetric and parallel voltammetric sensitivity to heroin metabolism in brain

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