Types Of Esterases Research Articles

EFFECT OF CARBON TETRACHLORIDE UPON ARYLESTERASES IN MICE

Early works by Augustinsson (1-4) demonstrated that three types of esterases exist in vertebrate plasma in regard to substrate specificity and susceptibility to selective inhibitors, and he classified them into arylesterases [EC 3. 1. 1. 2], aliesterases (carboxylesterases) [EC 3.1.1.1] and cholinesterases [EC 3.1.1.8]. However, physiological and clinical significance that the altered activities of these esterases imply is still obscure. Recently, Takahashi et al. (5) suggested that decrease in the activity of phenyl acetate esterase (corresponding to arylesterases, according to the Augustinsson's classification) was correlated with the degree of liver damage and that, clinically, the activity of the enzyme in serum decreased greatly in the case of liver cirrhosis. In the present paper, changes in the total activity and the electrophoretic pattern of arylesterases were studied in CCl4-induced mouse liver injury using β-naphthyl acetate as substrate.

A comparative study of vertebrate esterase multiplicity

1. 1. The properties of the multiple enzyme forms of soluble esterase activity have been studied in three non-mammalian species—lizard, frog and catfish. 2. 2. The resultant data has enabled a review and classification of esterase heterogeneity over a representative range of vertebrate phylogeny. 3. 3. Four main classes of esterase activity have been characterized (carboxyl-esterases, arylesterases, acetylesterases and cholinesterases), but evidence for further differentiation of activity-types within these groups is also presented. 4. 4. Considerable molecular variation is evident between species and a late evolutionary development of some esterase types (e.g. acetylesterases, group I carboxylesterases and cholinesterases) seems indicated.

Isozyme variability in species of the genus Drosophila. V. Ejaculatory bulb esterases in Drosophila phylogeny.

The presence or absence of certain esterase types in ejaculatory bulbs of 93 Drosophilaspecies was determined by appropriate staining after starch gel electrophoresis. One entire subgenus (Sophophora)and several primitive species were found lacking in one type of esterase. This esterase was present in numerous species of the large Drosophilasubgenus, but presence and absence did not follow closely the lines of taxonomic subdivisions in the subgenus. Correlation of presence-absence of the bulb esterase and previous results in interspecific hybridization tests indicated a greater chance for a successful interspecific cross when males possessed the bulb esterase.

Fractionation of peptidase and esterase activities of human cerebrospinal fluid

Human cerebrospinal fluid was collected, concentrated and fractionated by DEAE and Sephadex chromatography and starch-gel electrophoresis. Three peptidase components were distinguished. Each had its own pH optimum and a different substrate specificity, different affector characteristics and molecular weight. Two esterases and a non-specific choline esterase were distinguished by the chromatographic method and at least six separate esterases were distinguished by starch-gel electrophoresis. One of these components also hydrolysed substrates of the lipase type. The affector properties were also tested. It was observed that human cerebrospinal fluid contains more types of peptidases and esterases than earlier results have suggested. The possible secretion of enzymes from the brain and their significance for diagnosis are discussed.

Ultrastructural demonstration of acetylcholinesterase activity of motor endplates via osmiophilic diazothioethers.

The ultrastructural chemical localization of acetylcholinesterase of motor endplates of rat intercostal muscle has been studied with three new esterase substrates. These substrates, although not specific for acetylcholinesterase, have differential affinities for various types of esterases; two of them (NTA and TAB) are hydrolyzed preferentially by acetyl esterase enzymes, and the third (TPB) is a propionic acid ester and is hydrolyzed preferentially by pseudocholinesterase and other esterases. The end-product of the enzymatic reaction is converted to a diazothioether (droplet form) and upon osmication this is converted to a coordination polymer of osmium which has ideal properties for electron microscopy.

Comparative Studies on Estrase Zymograms among Various Tissues in the Silkworm, Bombyx mori L. : Lepidoptera : Bombycidae

By means of agar gel electrophoresis esterase zymograms of extracts from various tisues, singulary of individual larvae, were compared using a number of silkworm strains. Six major bands moving toward the anode were found with β-naphythyl acetate as the substrate and naphthanil diazoblue B as coupler. The fastest migrating intense bands A and B were detected in the mid-gut, and the less mobile esterase C was present in the silk gland. Esterases (E, F) detected in tracheas completely corresponded to integument esterase types. This phenomenon suggests that esterase bands in the integment and tracheas may be controlled by the same genes. The bands detected for the esterases in the integument correspond with the slow migrating bands of the Malpighian tubules. No similarity was noted among the esterase patterns obtained for the blood, mid-gut and silk gland and those of the integument or tracheae.

Analysis of the crystal antigens of Bacillus thuringiensis by gel diffusion.

Summary. The antigenic patterns of the crystal protein inclusions of Bacillus thuringiensis were determined. No specific antigenic patterns associated with previously described subgroups of this species were found. A larger number of categories of crystal antigen than of flagellar antigen or esterase type were found. In some cases isolates indistinguishable in classifications based on flagellar antigens or esterase types could be subdivided by their crystal antigenic pattern. The use of crystal antigens in classification is discussed.

The genetic control of two types of esterases in inbred strains of the mouse.

The genetic control of two types of esterases in inbred strains of the mouse.

GENETICO-BIOCHEMICAL ANALYSIS OF SPECIFIC ESTERASES IN <i>MUSCA DOMESTICA</i>

In order to classify the multiple molecular forms of esterases in house flies which can be revealed by unspecific substrates such as α- or β-naphthylacetate in thin-layer electrophoresis, substrate specificity and susceptibility to selective inhibitors have been studied. Specific esterases were revealed by using a pH-indicator method which can be applied to any substrate. The esterases hydrolysing acetylcholine, methyl-n-butyrate, ethyl-n-butyrate, tributyrin, phenylacetate and phenyl-n-butyrate were compared with esterases splitting β-naphthylacetate, and effects of eserine and TOCP (tri-o-cresyl phosphate) on their zymograms were studied. It is suggested that four types of esterases may be distinguished in house fly homogenates.Genetic analysis on a factor responsible for formation of the butylester-splitting enzyme which has a lower activity in diazinon resistant house flies showed that it is controlled by a recessive gene on the 5th chromosome, on which diazinon-resistance gene and the genes controlling the majority of esterase bands are already known to be located.

TYPES AND INHERITANCE OF BLOOD ESTERASE IN THE SILKWORM, <i>BOMBYX MORI</i> L.

By means of thin layer electrophoresis in agar gel, the zymograms of blood esterase of 161 silkworm strains was studied. Four fundamental types of esterase were found, and crossing experiments led to the conclusion that they are controlled by codominant alleles, BesA, BesB, BesC, and BesO. About 70% of the Japanese, Chinese and European races investigated belong to A type and 20% to O type, while B type was found only in Chinese race.

Distribution of the blood esterase types in various strains of the silkworm, Bombyx mori L

Distribution of the blood esterase types in various strains of the silkworm, Bombyx mori L

Some Physiological Aspects of Organogenesis in the Insect Embryo

AbstractIn the embryo, as in the postembryonic insect, morphological development is accompanied by an increase or change in enzyme activity. The appearance of certain enzymatically active proteins in a particular tissue or organ may indicate when that tissue or organ has become functional. The time and place of appearance of several types of esterase has been determined in the tissues and organs of the developing embryo of the large milkweed bug,Oncopeltus fasciatus(Dall.). The appearance of acetylcholinesterase in the neuropile of the nervous system reflects the morphological development of this system; it may also determine the onset of functional activity. Similarly, the appearance of non-specific esterase in many tissues and organs at a definite time during their morphological development suggests a relationship between their functional differentiation and the appearance of the enzyme. Evidence for such a relationship will remain circumstantial until the physiological significance of these esterases is understood.

On the esterase types in the mid-gut of the silkworm, Bombyx mori L.

On the esterase types in the mid-gut of the silkworm, Bombyx mori L.

CHARACTERISTICS OF THE ESTERASES OF HUMAN CELLS GROWN IN VITRO

When extracts of cultured human cells are subjected to starch-gel electrophoresis, as many as 17 bands of esterase activity can be observed. In addition to their different migratory characteristics in an electric field, the various bands can be shown to differ in their substrate preferences, their stability during pronlonged storage and during heating, and their interactions with inhibitors and activators. The abundance of types of esterase in these undifferentiated cells would seem to indicate a very important role for esterase reactions in cellular function.

THE EFFECTS OF SIALIDASE ON PSEUDOCHOLINESTERASE TYPES

Hereditary variants of human serum cholinesterase were exposed to the action of sialidase. The removal of the sialic acid residues had no effect on the kinetic properties of the esterases but greatly affected the electrophoretic mobility. In starch gel, there were no differences between the pseudocholinesterase types whether sialidase-treated or untreated. This observation permits two conclusions: first, the differences between the esterase types must reside in the protein cores, and second, the different variants must possess equal amounts of sialic acid per protein molecule. According to Liddell et al. there is a charge difference between esterase molecules of different type; since this cannot be accounted for by sialic acid content, the distinguishing characteristics are likely due to differences of amino acid composition.

THE EFFECTS OF SIALIDASE ON PSEUDOCHOLINESTERASE TYPES

Hereditary variants of human serum cholinesterase were exposed to the action of sialidase. The removal of the sialic acid residues had no effect on the kinetic properties of the esterases but greatly affected the electrophoretic mobility. In starch gel, there were no differences between the pseudocholinesterase types whether sialidase-treated or untreated. This observation permits two conclusions: first, the differences between the esterase types must reside in the protein cores, and second, the different variants must possess equal amounts of sialic acid per protein molecule. According to Liddell et al. there is a charge difference between esterase molecules of different type; since this cannot be accounted for by sialic acid content, the distinguishing characteristics are likely due to differences of amino acid composition.

Histochemical evidence of three types of esterases in the adrenal medulla of the rat.

Esterases of the adrenal medulla have been studied histochemically using alpha-naphthyl acetate and butyrate as substrates, Blue RR Salt as a coupler and eserine and E, 600 as inhibitors. Three types of esterase activity were thus demonstrated: (1) cholinesterase activity in the nerve fibres, ganglion cells and secretory medullary cells; (2) eserine resistant but E. 600 sensitive esterase activity in the ganglion cells and secretory cells; (3) E. 600 resistant activity in strongly positive, unidentified cells scattered in the medulla. The histochemical picture was essentially similar in sections of formalin-fixed tissue and in fresh sections subjected to the voltage gradient employed for electrophoretic separation of esterases. It is concluded that esterases histochemically demonstrable in sections are desmo-enzymes and at least to a major part different from the lyo-enzymes which can be separated by starch gel electrophoresis.

Some statistical data on atypical cholinesterase of human serum.

SummaryThe occurrence of atypical serum cholinesterase (pseudocholinesterase) was determined in a population which consisted of 2000 healthy persons and 2400 mental patients. The type of esterase was assessed by determining the Dibucaine Number (DN), i.e. the susceptibility of the esterase to inhibition.The distribution of DN in the population was consistent with the assumption of two autosomal allelic genes giving rise to two types of esterase. The frequency of the gene for atypical esterase in the healthy population was estimated to be 0.019 ± 0.002.The great majority of all investigated persons were of European extraction. There was no evidence for a different incidence of atypical esterase among Europeans, or between Europeans and North Americans, or between religious groups.The incidence of heterozygosity did not vary with age, sex, or body weight, although these three factors were correlated with esterase levels.There was no obvious relation between mental illness and incidence of atypical esterase but a connexion between some of the less common mental diagnoses and atypical esterase could not be excluded.

The activity of various esterase inhibitors towards atypical human serum cholinesterase

Guided by genetic studies, human sera were selected and postulated to contain either the usual type of serum cholinesterase (pseudocholinesterase), or an atypical variety of this enzyme, or a mixture of these two enzymes. The shape of concentration-inhibition curves obtained with sera of the last-named category permitted no other interpretation than the presence of a mixture of two enzymes. The concept of the existence of a usual and of an atypical form of human serum cholinesterase was thereby supported. The values for I 50 (concentration of inhibitor causing 50 per cent inhibition) of 16 inhibitors for normal and atypical esterase were compared under standard conditions. Both types of esterase were equally affected by the phosphate inhibitors DFP and TEPP. All other inhibitors blocked the atypical esterase less than the normal one. In relation to their usual blocking capacities, the bisquaternary compounds C 10 and succinylcholine were particularly weak inhibitors of the atypical esterase. For the 12 remaining inhibitors, which included tetramethylammonium, procaine, and eserine, the normal and atypical I 50 could be related by the exponential equation I 50-atypical = (I 50-usual) 0.785; that is, the difference between corresponding I 50-values increased with increasing potency of the inhibitors. Several compounds, e.g., decamethonium and chlorpromazine, were competitive inhibitors of atypical esterase, but they were not completely competitive inhibitors of the usual enzyme. Every fourth molecule of C 10 and of succinylcholine seemed to block two active centres of the normal esterase, but each of these molecules blocked only one active centre of the atypical enzyme.

The distribution of cholinesterases in cats and changes caused by hypophysectomy, adrenalectomy, undernutrition and DOCA.

Summary.1. The cholinesterase activity of the “true” and “pseudo” types of homogenized submaxillary gland, gastro‐intestinal mucosa and liver was determined in five groups of cats: 1) normal, 2) hypophysectomized, 3) adrenalectomized, 4) adrenalectomized maintained on DOCA, 5) undernourished.2. In normal cats the choliiiesterase of the submaxillary gland is predominantly of the “true” type, in the liver the “pseudo” type only could be found, in the gastric mucosa the “pseudo” type prevails beside merely detectable amounts of “true” esterasc. while the mucosa of the small intestine is abundant in both types of esterase.3. Hypophysectomy and adrenalectomy are followed by a coilsiderable increase in the concentrations of “true” and “pseudo” cholinesterase in the salivary gland. Similar changes occur in the intestinal mucosa after adrenalectomy, while they are absent in the liver and gastric mucosa.4. In adrenalectomized cats treatment with DOCA possibly had a slight (statistically not significant) effect in lowering the cholinesterase levels of the salivary gland towards normal, while no such effect was observed in the intestinal mucosa.5. In cats on reduced food a decrease in both types of esterase activity was found in the mucosa of the small intestine, whereas in the salivary gland, gastric mucosa and liver no changes were detectable.