PubMed Health⌕ Search

Biomedical subjects

L F Chasseaud

Publications and source records attributed to L F Chasseaud.

At least 163 records · Page 9Linked to original sources
PubMed1973

Distribution of enzymes that catalyse reactions of glutathione with alpha beta-unsaturated compounds.

1. A study of the distribution of glutathione S-alkenetransferases in the livers of vertebrate species suggests that different enzymes may catalyse reactions of GSH with (i) trans-benzylideneacetone, (ii) 2,3-dimethyl-4(2-methylenebutyryl)phenoxyacetic acid, (iii) cinnamonitrile, (iv) o-chlorobenzylidenemalononitrile, (v) methyl vinyl sulphone, and (vi) 3-(beta-nitrovinyl)indole. 2. Glutathione S-alkenetransferase activity was generally greatest in rat liver, but the enzyme in hamster liver was more active towards o-chlorobenzylidenemalononitrile, and the enzyme in rabbit, hamster, guinea-pig and mouse livers was more active towards methyl vinyl sulphone. 3. Results from studies of the distribution of activities in rat liver and rat kidney, heat inactivation of rat liver supernatants, and (NH(4))(2)SO(4) fractionation and acid-precipitation experiments, differentiated further between some of the enzymes concerned with substrates (i)-(vi). 4. The infrequent detection of mercapturic acids in vivo is discussed.

Adult↗
PubMed1969

Glutathione S-aralkyltransferase.

1. The name ;glutathione S-aralkyltransferase' is proposed for the enzyme catalysing the reaction of benzyl chloride with GSH. 2. Results from heat-inactivation studies, ammonium sulphate-fractionation and acid-precipitation experiments, and studies of the distribution of activities in rat liver, in rat kidney and in the livers of other animals indicate that glutathione S-aralkyltransferase differs from glutathione S-alkyltransferase, S-aryltransferase, S-epoxidetransferase and an S-alkenetransferase. 3. The distribution of these enzymes in the livers of the animal species examined was different. 4. Glutathione S-alkyltransferase, S-aralkyltransferase and the S-alkenetransferase that are present in rat liver supernatant were inhibited by GSSG, and the nature of the inhibition varied in each case. 5. 3,5-Di-tert.-butyl-4-hydroxybenzyl acetate reacts spontaneously with GSH, but the rat liver-supernatant-catalysed reaction of GSH with this and other aralkyl esters was weak. 6. A probable function of the glutathione S-transferases is the protection of cellular constituents from strong electrophilic agents.

Animals↗
PubMed1968

Enzymes catalysing conjugations of glutathione with alpha-beta-unsaturated carbonyl compounds.

1. Heat-inactivation experiments, ammonium sulphate-fractionation studies, enzyme-inhibition studies with S-(alphabeta-diethoxycarbonylethyl)glutathione, and evidence from the distribution of activities in rat liver, in rat kidney and in the livers of other animals, indicate that reactions of glutathione with (i) trans-benzylideneacetone, (ii) cyclohex-2-en-1-one, (iii) trans-cinnamaldehyde, (iv) diethyl maleate, (v) diethyl fumarate and (vi) 2,3-dimethyl-4-(2-methylenebutyryl)phenoxyacetic acid are catalysed by different enzymes. 2. Evidence is presented that the enzymes catalysing the reactions of glutathione with substrates (i)-(iv) are different from glutathione S-alkyltransferase, S-aryltransferase and S-epoxidetransferase. 3. The name ;glutathione S-alkenetransferases' is proposed for enzymes catalysing reactions of glutathione with alphabeta-unsaturated compounds. 4. The Arrenhius plot for the enzyme-catalysed reaction of diethyl maleate with glutathione is discontinuous, with lower energy of activation at 38 degrees .

Aldehydes↗
PubMed1967

Enzyme-catalysed conjugations of glutathione with unsaturated compounds.

1. Rat-liver supernatant catalyses the reaction of diethyl maleate with glutathione. 2. Evidence is presented that the enzyme involved is different from the known glutathione-conjugating enzymes, glutathione S-alkyltransferase, S-aryltransferase and S-epoxidetransferase. 3. Rat-liver supernatant catalyses the reaction of a number of other alphabeta-unsaturated compounds, including aldehydes, ketones, lactones, nitriles and nitro compounds, with glutathione: separate enzymes may be responsible for these reactions.

Acids↗
PubMedDate not supplied

Plasma concentrations and pharmacokinetics of dihydralazine after single oral doses to human subjects.

After single oral doses of 20 mg of a suspension of dihydralazine sulphate to human subjects, the peak of mean plasma concentrations of dihydralazine of 47.0 ng ml-1 +/- 11.0 standard deviation (S.D.) (n = 7) was reached at 1 h. Mean concentrations declined biphasically with apparent half-lives of 0.57 and 4.96 h respectively. Dihydralazine was partly converted to hydralazine. The peak of mean plasma concentrations of the latter drug of 3.9 ng ml-1 +/- 1.7 S.D. (n = 7) occurred at 1-2 h after dosing with dihydralazine sulphate and declined to 1.5 ng ml-1 +/- 1.5 S.D. at 6 h. Of the seven subjects studied, three were classified as fast and four as slow acetylators. Mean clearances appeared to be slightly more rapid in fast acetylators (1.63 l min-1 +/- 0.32 S.D.) when compared to slow acetylators (1.31 l min-1 +/- 0.31 S.D.) but this difference and differences in plasma concentrations and in areas under the plasma drug concentration-time curves were not significant (p > 0.1).

Acetylation↗