scholarly journals The Metabolism of Gammekane and Related Compounds

2021 ◽  
Author(s):  
◽  
Alan Geoffrey Clark
Keyword(s):  
Liver Enzyme ◽  
Gel Filtration ◽  
Dicarboxylic Acids ◽  
In Vitro Metabolism ◽  
Enzyme Preparations ◽  
Sheep Liver ◽  
Lysine Residues ◽  
Complete Exclusion

<p>1. A detailed kinetic study has been made of the glutathione S-aryl-transferases from the New Zealand grass grub (Costelytra zealandica) and from sheep liver. The insect enzyme behaves in accordance with a Michaelis-Menten model for two-substrate enzymes. It is inhibited by the sulphonphthaleins, phthaleins, fluoresceins and dicarboxylic acids competing with glutathione, while the sheep-liver enzyme is not susceptible to this type of inhibition. From this, and other data obtained from a study of the variation of kinetics with pH, it is proposed that two basic groups (possibly lysine residues) are involved in binding of glutathione to the insect enzyme, while only one such group appears in the sheep-liver enzyme. Binding of the aromatic substrate to the enzyme in both species may involve a histidine residue. 2. The accumulation of little significant radioactivity in diluant 2gamma-pentachlorocyclohexene (gamma-PCCH) during the in vitro metabolism of [14C]gamma-hexachlorohexane (gamma-HCH) suggests that the PCCH's are not formed as free intermediates during the metabolism of the HCH's. However, certain ambiguities introduced with the experimental techniques used preclude the complete exclusion of this possibility. 3. gamma-HCH, gamma-PCCH and delta-PCCH metabolized in vivo by M.domestica and C.zealandica and in vitro by preparations from both species, all produce as the principal metabolite a glutathione conjugate with chromatographic properties identical with those of authentic S-(2,4-dichlorophenyl)glutathione. There is, however some doubt as to the identity of the S-substituent moiety. 4. The in vitro metabolism of gamma-HCH and delta-PCCH is glutathione-dependent and is inhibited by various phthaleins and sulphonphthaleins. The in vivo metabolism of delta-PCCH in C.zealandica is profoundly affected by this type of compound, but its effects on the rate of metabolism in vivo of delata-HCH in M.domestica and C.zealandica are only marginal. 5. The enzyme concerned in the metabolism of delta-PCCH has been shown to differ from aryltransferase in M.domestica and C.zealandica by gel filtration techniques and by differences in activity in different enzyme preparations. The delta-PCCH-metabolising activity appears to be associated with a DDT dehydrochlorinase activity. In M.domestica, there appears to be, in addition, a second DDT dehydrochlorinase with only a low cross-specificity towards delta-PCCH.</p>

scholarly journals The Metabolism of Gammekane and Related Compounds

2021 ◽  
Author(s):  
◽  
Alan Geoffrey Clark
Keyword(s):  
Liver Enzyme ◽  
Gel Filtration ◽  
Dicarboxylic Acids ◽  
In Vitro Metabolism ◽  
Enzyme Preparations ◽  
Sheep Liver ◽  
Lysine Residues ◽  
Complete Exclusion

<p>1. A detailed kinetic study has been made of the glutathione S-aryl-transferases from the New Zealand grass grub (Costelytra zealandica) and from sheep liver. The insect enzyme behaves in accordance with a Michaelis-Menten model for two-substrate enzymes. It is inhibited by the sulphonphthaleins, phthaleins, fluoresceins and dicarboxylic acids competing with glutathione, while the sheep-liver enzyme is not susceptible to this type of inhibition. From this, and other data obtained from a study of the variation of kinetics with pH, it is proposed that two basic groups (possibly lysine residues) are involved in binding of glutathione to the insect enzyme, while only one such group appears in the sheep-liver enzyme. Binding of the aromatic substrate to the enzyme in both species may involve a histidine residue. 2. The accumulation of little significant radioactivity in diluant 2gamma-pentachlorocyclohexene (gamma-PCCH) during the in vitro metabolism of [14C]gamma-hexachlorohexane (gamma-HCH) suggests that the PCCH's are not formed as free intermediates during the metabolism of the HCH's. However, certain ambiguities introduced with the experimental techniques used preclude the complete exclusion of this possibility. 3. gamma-HCH, gamma-PCCH and delta-PCCH metabolized in vivo by M.domestica and C.zealandica and in vitro by preparations from both species, all produce as the principal metabolite a glutathione conjugate with chromatographic properties identical with those of authentic S-(2,4-dichlorophenyl)glutathione. There is, however some doubt as to the identity of the S-substituent moiety. 4. The in vitro metabolism of gamma-HCH and delta-PCCH is glutathione-dependent and is inhibited by various phthaleins and sulphonphthaleins. The in vivo metabolism of delta-PCCH in C.zealandica is profoundly affected by this type of compound, but its effects on the rate of metabolism in vivo of delata-HCH in M.domestica and C.zealandica are only marginal. 5. The enzyme concerned in the metabolism of delta-PCCH has been shown to differ from aryltransferase in M.domestica and C.zealandica by gel filtration techniques and by differences in activity in different enzyme preparations. The delta-PCCH-metabolising activity appears to be associated with a DDT dehydrochlorinase activity. In M.domestica, there appears to be, in addition, a second DDT dehydrochlorinase with only a low cross-specificity towards delta-PCCH.</p>

scholarly journals Glutathione transferase Zeta catalyses the oxygenation of the carcinogen dichloroacetic acid to glyoxylic acid

1998 ◽  
Vol 331 (2) ◽  
pp. 371-374 ◽  
Author(s):  
Zeen TONG ◽  
Philip G. BOARD ◽  
M. W. ANDERS
Keyword(s):  
Liver Enzyme ◽  
Rat Liver ◽  
Glutathione Transferase ◽  
Gel Filtration ◽  
Rabbit Antiserum ◽  
Glyoxylic Acid ◽  
Dichloroacetic Acid ◽  
Amino Acid Residues

Dichloroacetic acid (DCA), a common drinking-water contaminant, is hepatocarcinogenic in rats and mice, and is a therapeutic agent used clinically in the management of lactic acidosis. DCA is biotransformed to glyoxylic acid by glutathione-dependent cytosolic enzymes in vitro and is metabolized to glyoxylic acid in vivo. The enzymes that catalyse the oxygenation of DCA to glyoxylic acid have not, however, been identified or characterized. In the present investigation, an enzyme that catalyses the glutathione-dependent oxygenation of DCA was purified to homogeneity (587-fold) from rat liver cytosol. SDS/PAGE and HPLC gel-filtration chromatography showed that the purified enzyme had a molecular mass of 27–28 kDa. Sequence analysis showed that the N-terminus of the purified protein was blocked. An internal sequence of 30 amino acid residues was obtained that matched the recently discovered human glutathione transferase Zeta well [Board, Baker, Chelvanayagam and Jermiin (1997) Biochem. J. 328, 929–935]. Western-blot analysis showed that the purified rat-liver enzyme cross-reacted with rabbit antiserum raised against recombinant human glutathione transferase Zeta. The apparent Km and Vmax values of the purified enzyme with DCA as the variable substrate were 71.4 µM and 1334 nmol/min per mg of protein, respectively; the Km for glutathione was 59 µM. Both the purified rat-liver enzyme and the recombinant human enzyme showed high activity with DCA as the substrate. These results demonstrate that the glutathione-dependent oxygenation of DCA to glyoxylic acid is catalysed by a Zeta-class glutathione transferase.

Purification of the Antihemophilic Factor by Gel Filtration on Agarose

1969 ◽  
Vol 22 (03) ◽  
pp. 577-583 ◽  
Author(s):  
M.M.P Paulssen ◽  
A.C.M.G.B Wouterlood ◽  
H.L.M.A Scheffers
Keyword(s):  
Factor Viii ◽  
Plasma Proteins ◽  
Large Scale ◽  
Gel Filtration ◽  
Large Scale Preparation ◽  
Scale Preparation ◽  
Antihemophilic Factor

SummaryFactor VIII can be isolated from plasma proteins, including fibrinogen by chromatography on agarose. The best results were obtained with Sepharose 6B. Large scale preparation is also possible when cryoprecipitate is separated by chromatography. In most fractions containing factor VIII a turbidity is observed which may be due to the presence of chylomicrons.The purified factor VIII was active in vivo as well as in vitro.

Half-Life of Platelet Factor 4 (PF-4) in Plasma and Platelets from Macaca Mulatta

1977 ◽  
Vol 37 (01) ◽  
pp. 073-080 ◽  
Author(s):  
Knut Gjesdal ◽  
Duncan S. Pepper
Keyword(s):  
Macaca Mulatta ◽  
Half Life ◽  
Human Platelet ◽  
Gel Filtration ◽  
Platelet Factor 4 ◽  
Active Protein ◽  
Platelet Factor ◽  
Membrane Bound

SummaryHuman platelet factor 4 (PF-4) showed a reaction of complete identity with PF-4 from Macaca mulatta when tested against rabbit anti-human-PF-4. Such immunoglobulin was used for quantitative precipitation of in vivo labelled PF-4 in monkey serum. The results suggest that the active protein had an intra-platelet half-life of about 21 hours. In vitro 125I-labelled human PF-4 was injected intravenously into two monkeys and isolated by immuno-precipita-tion from platelet-poor plasma and from platelets disrupted after gel-filtration. Plasma PF-4 was found to have a half-life of 7 to 11 hours. Some of the labelled PF-4 was associated with platelets and this fraction had a rapid initial disappearance rate and a subsequent half-life close to that of plasma PF-4. The results are compatible with the hypothesis that granular PF-4 belongs to a separate compartment, whereas membrane-bound PF-4 and plasma PF-4 may interchange.

Biochemical and pharmacokinetic characterisation of two PEGylated variants of dipetarudin

2009 ◽  
Vol 102 (09) ◽  
pp. 454-459 ◽  
Author(s):  
Anne Koehler ◽  
Goetz Nowak ◽  
Mercedes López
Keyword(s):  
Gel Filtration ◽  
Pharmacokinetic Profile ◽  
Peripheral Compartment ◽  
Therapeutic Application ◽  
Similar Activity ◽  
Elimination Half ◽  
K 12 ◽  
Extravascular Compartment

SummaryDipetarudin was coupled to polyethylene glycol (PEG)-5000 residues in order to improve its pharmacokinetic profile and to enhance its anticoagulant efficacy. The resulting compounds, mono-and di-PEGylated dipetarudin were purified by gel filtration. Mono-PEGylated dipetarudin exhibited similar activity like its non-conjugated equivalent both in vitro and in vivo. However, di-PEGylated dipetarudin showed longer distribution and elimination half-lives and higher area under the time-concentration curve in comparison with the unmodified inhibitor which may be attributed to decreased renal clearance. Futhermore, ratio k 12/k 21 decreased when the number of PEG chains coupled to dipetarudin increased. It means that the intercompartment transfer of dipetarudin, characterised by a fast distribution and a high retention in the peripheral compartment, is reverted by coupling to PEG. Thus, the transfer of mono-PEGylated dipetarudin between these compartments is similar in both senses and the transfer of di-PEGylated dipetarudin is slower from vascular to extravascular compartment than vice versa. Our results show that di-PEGylated dipetarudin produces a better and longer anticoagulant effect than unmodified dipetarudin which is a desirable attribute for future therapeutic application.

scholarly journals Lysyl oxidase activity and elastin/glycosaminoglycan interactions in growing chick and rat aortas.

1987 ◽  
Vol 105 (3) ◽  
pp. 1463-1469 ◽  
Author(s):  
C Fornieri ◽  
M Baccarani-Contri ◽  
D Quaglino ◽  
I Pasquali-Ronchetti
Keyword(s):  
Hydrophobic Interactions ◽  
Isonicotinic Acid ◽  
Lysyl Oxidase ◽  
Acid Hydrazide ◽  
Elastic Fibers ◽  
Amino Groups ◽  
Lysine Residues ◽  
Oxidase Inhibition

Hydrophobic tropoelastin molecules aggregate in vitro in physiological conditions and form fibers very similar to natural ones (Bressan, G. M., I. Pasquali Ronchetti, C. Fornieri, F. Mattioli, I. Castellani, and D. Volpin, 1986, J. Ultrastruct. Molec. Struct. Res., 94:209-216). Similar hydrophobic interactions might be operative in in vivo fibrogenesis. Data are presented suggesting that matrix glycosaminoglycans (GAGs) prevent spontaneous tropoelastin aggregation in vivo, at least up to the deamination of lysine residues on tropoelastin by matrix lysyl oxidase. Lysyl oxidase inhibitors beta-aminopropionitrile, aminoacetonitrile, semicarbazide, and isonicotinic acid hydrazide were given to newborn chicks, to chick embryos, and to newborn rats, and the ultrastructural alterations of the aortic elastic fibers were analyzed and compared with the extent of the enzyme inhibition. When inhibition was greater than 65% all chemicals induced alterations of elastic fibers in the form of lateral aggregates of elastin, which were always permeated by cytochemically and immunologically recognizable GAGs. The number and size of the abnormal elastin/GAGs aggregates were proportional to the extent of lysyl oxidase inhibition. The phenomenon was independent of the animal species. All data suggest that, upon inhibition of lysyl oxidase, matrix GAGs remain among elastin molecules during fibrogenesis by binding to positively charged amino groups on elastin. Newly synthesized and secreted tropoelastin has the highest number of free epsilon amino groups, and, therefore, the highest capability of binding to GAGs. These polyanions, by virtue of their great hydration and dispersing power, could prevent random spontaneous aggregation of hydrophobic tropoelastin in the extracellular space.

Age-dependent changes in volume and haemoglobin content of erythrocytes in the carp (Cyprinus carpio L.)

1989 ◽  
Vol 141 (1) ◽  
pp. 133-149 ◽  
Author(s):  
W. Speckner ◽  
J. F. Schindler ◽  
C. Albers
Keyword(s):  
Gel Filtration ◽  
Linear Increase ◽  
Human Erythrocytes ◽  
Main Peak ◽  
Red Cell ◽  
Human Haemoglobin ◽  
Cell Fractions ◽  
Haemoglobin Content

Carp erythrocytes were fractionated by angle-head centrifugation which yielded fractions with a linear increase in density. Haematological examinations revealed that the heavier red blood cells of carp had greater volumes (MCV), more haemoglobin (MCH) and higher haemoglobin concentrations (MCHC) than light ones. The same experiments with human red cell fractions yielded a decrease in MCV, constant MCH and an increase in MCHC. Haemoglobin content in individual erythrocytes was also determined by scanning stage absorbance cytophotometry to establish the frequency distribution of the cellular haemoglobin contents. In carp, the distribution was symmetrical with the means increasing with density. No such change with cell density was found in human erythrocytes. Both carp and human erythrocytes incorporated [2-14C]glycine in vitro. After gel filtration, radioactivity was detected in carp, but not in human, haemoglobin fractions. 14C was found in all three haemoglobin fractions, obtained by isoelectric focusing, and was present in the haem and in the globin. [2-14C]glycine-labelled erythrocytes were reinjected into chronically cannulated carp and followed in vivo for several months. With time, the main peak of scintillation counts shifted from red cell fractions of low to high density. This is considered as evidence that density and age of red cells in carp are positively correlated and that erythrocytes can synthesize haemoglobin while circulating in the peripheral blood.

Characterization of the Metamitron Deaminating Enzyme Activity from Sugar Beet ( Beta vulgaris L.) Leaves

1979 ◽  
Vol 34 (11) ◽  
pp. 948-950 ◽  
Author(s):  
Carl Fedtke ◽  
Robert R. Schmidt
Keyword(s):  
Cytochrome C ◽  
Sugar Beet ◽  
Electron Donor ◽  
Nitrogen Atmosphere ◽  
Enzyme Preparations ◽  
Reducing Conditions ◽  
Trade Name ◽  
Membrane Bound

Abstract The enzymatic activity from sugar beet leaves which is responsible for the detoxification of the herbicide metamitron (4-amino-4,5-dihydro-3-methyl-6-phenyl-1, 2, 4-triazin-5-one, trade name Goltix®) has been characterized in vitro. The detoxification occurs by rapid deamination in vivo as well as in vitro. However, the deamination in vitro is only maximal under reducing conditions, i. e. with an electron donor and in a nitrogen atmosphere. The electron donor may be cystein, glutathione, dithionite or ascorbate. The enzymatic deamination further requires the addition of cytochrome c and a “supernatant factor”, which may be replaced by FMN, FAD or DCPIP. However, in the presence of FMN or DCPIP cytochrome c is not essential but only stimulatory. The partic­ulate as well as the soluble metamitron deaminating enzyme preparations obtained take up oxygen when supplied with cysteine and FMN. The particulate enzyme appears in the peroxysome-fraction. It is therefore suggested, that the enzymatic deamination of metamitron in sugar beet leaves is mediated by a proxisomal membrane bound electron transport system which alternatively may reduce oxygen or metamitron (deaminating).

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