Characterization of Canine Hepatic and Renal Esterases

1973 ◽  
Vol 51 (5) ◽  
pp. 506-513 ◽  
Author(s):  
D. J. Ecobichon
Keyword(s):  
Cholinesterase Activity ◽  
Kinetic Characteristics ◽  
Migration Patterns ◽  
Tissue Extracts ◽  
Liver And Kidney ◽  
Inhibition Studies ◽  
Hydrolysis Of ◽  
Naphthyl Acetate ◽  
Substrate Hydrolysis

The esterases of canine liver and kidney were separated electrophoretically into nine bands with identical migration patterns in both tissues. An additional pair of rapidly migrating anodic bands were observed in hepatic extracts. Based on substrate specificity, the predominant tissue esterases were identified as nonspecific carboxylesterases (aliesterases). No cholinesterase activity was detected in the tissue extracts. Kinetic characteristics determined for the hepatic and renal esterases included (1) optimal pH; (2) Km values for esters of α-naphthyl and p-nitrophenol; (3) average rates of hydrolysis of α-naphthyl acetate and p-nitrophenyl acetate by the tissue extracts. Inhibition studies revealed the presence of two types of esterase activity in each tissue: one type being sensitive to organophosphorus esters, the second being resistant. A study of preferential substrate hydrolysis in the presence of known characteristic activators and inhibitors of esterases revealed approximately 5% and 20% arylesterase activity in liver and kidney, respectively. The presence of arylesterase activity in these tissues was confirmed by the hydrolysis of paraoxon (E600).

LOCALIZATION AND CHARACTERIZATION OF CHOLINESTERASE IN SUBCELLULAR FRACTIONS OF RAT BRAIN AND BEEF PITUITARY

1961 ◽  
Vol 39 (9) ◽  
pp. 1335-1345 ◽  
Author(s):  
Surendra S. Parmar ◽  
Morley C. Sutter ◽  
Mark Nickerson
Keyword(s):  
Rat Brain ◽  
Cholinesterase Activity ◽  
Succinic Dehydrogenase ◽  
Anterior Lobe ◽  
Subcellular Fractions ◽  
Posterior Pituitary ◽  
Low Concentrations ◽  
Pituitary Glands ◽  
Hydrolysis Of

Fresh rat brains and fresh anterior and posterior pituitary glands of beef were separated by differential centrifugation into subcellular fractions, characterized on the basis of sedimentation and succinic dehydrogenase activity. Cholinesterase activity was measured by both manometric and colorimetric methods, the results of which were comparable. Cholinesterase activity of rat brain was found mainly in the microsome and supernatant fractions. It was quite uniformly distributed in all subcellular fractions of both anterior and posterior pituitary. Comparisons of the relative rates of hydrolysis of acetylthiocholine and butyrylthiocholine, and of inhibition by eserine, indicated that brain contains a much higher percentage of acetylcholinesterase than do both lobes of the pituitary, which contain relatively low concentrations of the specific enzyme. Total cholinesterase activity and its sensitivity to inhibition by eserine in the posterior pituitary were found to be midway between those of the anterior lobe and of the brain, from which the posterior pituitary was derived during embryological development.

Malathion-specific resistance in a strain of the rust red grain beetle Cryptolestes ferrugineus (Coleoptera: Cucujidae)

1998 ◽  
Vol 88 (2) ◽  
pp. 199-206 ◽  
Author(s):  
A.G. Spencer ◽  
N.R. Price ◽  
A. Callaghan
Keyword(s):  
Resistant Strain ◽  
Specific Resistance ◽  
Strain Differences ◽  
Gas Chromatography Mass Spectrometry ◽  
Cryptolestes Ferrugineus ◽  
Tributyl Phosphorotrithioate ◽  
Inhibition Studies ◽  
Hydrolysis Of ◽  
Naphthyl Acetate

AbstractA strain of Cryptolestes ferrugineus (Stephens) bred for malathion-specific resistance was found to be 650 fold resistant at LD50 when compared with a susceptible strain bred from the same stock. Resistance was more than 98% synergized by triphenyl phosphate and S,S,S-tributyl phosphorotrithioate, but unaffected by piperonyl butoxide. AChE inhibition by malaoxon varied slightly between the strains. Non-specific esterase activity as measured by the hydrolysis of α-naphthyl acetate was slightly reduced in the resistant strain whereas there were no inter-strain differences in the hydrolysis of β-naphthyl acetate. Products of in vitro metabolism of malathion were identified by thin-layer chromatography and gas chromatography-mass spectrometry as α- and β-malathion mono-acids. It was therefore concluded that resistance was due to the hydrolytic breakdown of malathion by a malathion-specific carboxylesterase. The rate of in vitro malathion hydrolysis was found to be 31 times greater in the resistant strain. In vitro inhibition studies indicated that resistance is attributable to a carboxylesterase unique to the resistant strain. The implications of these results are discussed in relation to work recently carried out on malathion-specific resistance in dipterous species.

Characterization of 2β(R)-17-O-AcetylajmaIan: Acetylesterase — a Specific Enzyme Involved in the Biosynthesis of the Rauwolfia Alkaloid Ajmaline

1987 ◽  
Vol 42 (4) ◽  
pp. 333-342 ◽  
Author(s):  
Leo Polz ◽  
Helmut Schübel ◽  
Joachim Stoekigt
Keyword(s):  
Substrate Selectivity ◽  
Specific Enzyme ◽  
Naturally Occurring ◽  
Optimum Ph ◽  
Relative Molecular Weight ◽  
Inhibition Studies ◽  
Hydrolysis Of ◽  
Activity Point ◽  
Rauwolfia Alkaloid

A novel enzyme was isolated, partially purified (217-fold) and characterized from cell suspen­sion cultures of Rauwolfia serpentina Benth. The enzyme catalyzes one of the late biochemical reactions in the biosynthesis of ajmaline by hydrolysis of 17-O-acetylated alkaloids of the ajmalan group forming the appropriate deacetylated compounds. This esterase exhibits an unusually high substrate selectivity and exclusively accepts acetylated ajmaline derivatives with the naturally occurring 2β(R)-configuration. The properties of the enzyme were determined showing an optimum pH at 7.5, an isoelectric point of pH 4.9 and a relative molecular weight of 33 ± 2 kDa. Inhibition studies of enzyme activity point to the necessity of SH-groups. The esterase seems not to be inhibited by ajmaline. the end product of the pathway. The highest enzyme activities were observed in leaves and cell suspension tissues of the tribe Rauwolfieae which are known to synthe­size ajmaline and its congeners. The specific function of the esterase in the biosynthesis of the later alkaloids was established.

Characterization of the esterases of canine serum

1970 ◽  
Vol 48 (12) ◽  
pp. 1359-1367 ◽  
Author(s):  
D. J. Ecobichon
Keyword(s):  
Close Association ◽  
Gel Filtration ◽  
Spectrophotometric Analysis ◽  
Specific Substrate ◽  
Starch Gel ◽  
Males And Females ◽  
Canine Serum ◽  
Hydrolysis Of ◽  
Naphthyl Acetate

Various techniques including electrophoresis, gel filtration, and titrimetric and spectrophotometric analysis with specific and nonspecific substrates and inhibitors were used to characterize the serum esterases of male and female dogs. Electrophoresis in starch gel yielded 10 distinct bands of activity: four butyrylcholinesterase bands, an esterolytically active albumin, and five bands of aliesterase and/or arylesterase activity. Gel filtration on Sephadex G-200 yielded two distinct peaks of activity, one containing the cholinesterase bands, and the second peak containing both arylesterase and aliesterase activity in close association with the serum albumin. Kinetic characteristics determined for the canine serum esterases included (1) optimal pH; (2) Km values for esters of choline, α-naphthol, and p-nitrophenol; and (3) average rates of hydrolysis of α-naphthyl acetate, butyrylcholine iodide, p-nitrophenyl acetate, and E600 by the sera of males and females. The sensitivity of the serum esterases to inhibition by various cations, and specific and nonspecific inhibitors was investigated. The organophosphate, E600, may be a highly specific substrate for the detection and quantification of arylesterase in a mixture of nonspecific carboxylesterases.

CHARACTERIZATION OF RAT LIVER AND KIDNEY ESTERASES

1967 ◽  
Vol 45 (4) ◽  
pp. 451-455 ◽  
Author(s):  
W. S. Schwark ◽  
D. J. Ecobichon
Keyword(s):  
Female Rats ◽  
Electrophoretic Separation ◽  
Male And Female ◽  
Male And Female Rats ◽  
Vertical Zone ◽  
Zone Electrophoresis ◽  
Liver And Kidney ◽  
Starch Gel ◽  
Inhibition Studies

Vertical zone electrophoresis in starch gel was employed in conjunction with various histochemical techniques to characterize the liver and kidney esterases of male and female rats. Tissue-specific patterns were observed for each organ and a sex-dependent difference was noted on electrophoretic separation of the liver extracts. On the basis of substrate specificity and inhibitor sensitivity, both organs were observed to contain similar nonspecific aliesterases or carboxylesterases (EC 3.1.1.1). Inhibition studies showed the presence of two types of aliesterase in the liver and kidney extracts.

scholarly journals Cloning, Expression and Characterization of a Novel Cold-adapted β-galactosidase from the Deep-sea Bacterium Alteromonas sp. ML52

Marine Drugs ◽  
2018 ◽  
Vol 16 (12) ◽  
pp. 469 ◽  
Author(s):  
Jingjing Sun ◽  
Congyu Yao ◽  
Wei Wang ◽  
Zhiwei Zhuang ◽  
Junzhong Liu ◽  
...  
Keyword(s):  
Deep Sea ◽  
Glycoside Hydrolase ◽  
Sea Water ◽  
Maximum Activity ◽  
Glycoside Hydrolase Family ◽  
Cold Adapted ◽  
Hydrolysis Of ◽  
Hydrolase Family ◽  
Substrate Hydrolysis

The bacterium Alteromonas sp. ML52, isolated from deep-sea water, was found to synthesize an intracellular cold-adapted β-galactosidase. A novel β-galactosidase gene from strain ML52, encoding 1058 amino acids residues, was cloned and expressed in Escherichia coli. The enzyme belongs to glycoside hydrolase family 2 and is active as a homotetrameric protein. The recombinant enzyme had maximum activity at 35 °C and pH 8 with a low thermal stability over 30 °C. The enzyme also exhibited a Km of 0.14 mM, a Vmax of 464.7 U/mg and a kcat of 3688.1 S−1 at 35 °C with 2-nitrophenyl-β-d-galactopyranoside as a substrate. Hydrolysis of lactose assay, performed using milk, indicated that over 90% lactose in milk was hydrolyzed after incubation for 5 h at 25 °C or 24 h at 4 °C and 10 °C, respectively. These properties suggest that recombinant Alteromonas sp. ML52 β-galactosidase is a potential biocatalyst for the lactose-reduced dairy industry.

scholarly journals CHARACTERIZATION OF ENZYMES HYDROLYZING ACYL NAPHTHYLAMIDES: II. TRIHALOGEN DERIVATIVES

1965 ◽  
Vol 13 (2) ◽  
pp. 117-124 ◽  
Author(s):  
V. K. HOPSU ◽  
R. S. SANTTI ◽  
G. G. GLENNER
Keyword(s):  
Species Differences ◽  
Deae Cellulose ◽  
Starch Gel Electrophoresis ◽  
Enzymic Hydrolysis ◽  
Hydrolysis Rates ◽  
Starch Gel ◽  
Acylase I ◽  
Hydrolysis Of ◽  
Substrate Hydrolysis

Enzymes in guinea pig homogenates hydrolyzing a variety of halogenated and nonhalogenated acyl α- and β-naphthylamide substrates can be separated into two major groups on the basis of substrate hydrolysis rates, solubility and affector characteristics. Both groups of enzymes, those acting on the non-, mono- and dihalogenated acyl naphthylamides and those acting on trihalogen derivatives, have characteristics like those of arylesterases and are inseparable from enzymes hydrolyzing naphthol AS acetate. These enzymes are, However, separable on fractionation by starch gel electrophoresis and DEAE-cellulose chromatography from several enzymes catalyzing the hydrolysis of N-acyl amino acids (acylase I and II) and several amino acid β-naphthylamides. Species differences exist in the characteristics of enzymic hydrolysis of these acylarylamides.

EFFECTS OF OVARIAN STEROID HORMONES ON ESTERASES IN THE RAT ENDOMETRIUM

1975 ◽  
Vol 64 (3) ◽  
pp. 465-NP ◽  
Author(s):  
D. P. BOSHIER ◽  
JUNE M. KATZ
Keyword(s):  
Neutral Lipids ◽  
Mature Female ◽  
Female Rats ◽  
Luminal Epithelium ◽  
Tissue Extracts ◽  
Periodic Stimulation ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Naphthyl Acetate ◽  
Stimulation Of

SUMMARY A technique in which uterine luminal epithelium is separated from the remainder of the endometrium by rapidly vibrating everted uterine cornua in a 3·5 mm solution of EDTA has been developed. Examination of the hormonal sensitivities and physiological roles of the tissue components of the endometrium is thus facilitated. Biochemical and histochemical studies of epithelial, stromal and endometrial esterases have shown that the rate of hydrolysis of α-naphthyl acetate is significantly higher in epithelial and endometrial tissue extracts during pro-oestrus than at any other stage of the oestrous cycle. In ovariectomized animals, oestradiol-17β caused a 60% increase in the rate of esterase activity over that of control animals, whereas medroxyprogesterone acetate had no effect. These findings suggest that the variations in the levels of neutral lipids in the uterine luminal epithelium of non-pregnant mature female rats result from the periodic stimulation of the epithelial esterases by the cyclically increased levels of plasma oestrogens.

Isolation and Characterization of Plasminogen Activator from Pig Leucocytes

1974 ◽  
Vol 31 (01) ◽  
pp. 072-085 ◽  
Author(s):  
M Kopitar ◽  
M Stegnar ◽  
B Accetto ◽  
D Lebez
Keyword(s):  
Molecular Weight ◽  
Plasminogen Activator ◽  
Gel Electrophoresis ◽  
Gel Filtration ◽  
Ph Optimum ◽  
Isolation And Characterization ◽  
Ph Range ◽  
Inhibition Studies ◽  
Final Purification

SummaryPlasminogen activator was isolated from disrupted pig leucocytes by the aid of DEAE chromatography, gel filtration on Sephadex G-100 and final purification on CM cellulose, or by preparative gel electrophoresis.Isolated plasminogen activator corresponds No. 3 band of the starting sample of leucocyte cells (that is composed from 10 gel electrophoretic bands).pH optimum was found to be in pH range 8.0–8.5 and the highest pH stability is between pH range 5.0–8.0.Inhibition studies of isolated plasminogen activator were performed with EACA, AMCHA, PAMBA and Trasylol, using Anson and Astrup method. By Astrup method 100% inhibition was found with EACA and Trasylol and 30% with AMCHA. PAMBA gave 60% inhibition already at concentration 10–3 M/ml. Molecular weight of plasminogen activator was determined by gel filtration on Sephadex G-100. The value obtained from 4 different samples was found to be 28000–30500.

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