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J Booth

Publications and source records attributed to J Booth.

At least 91 records · Page 5Linked to original sources
PubMed1975

Enzymic reduction of aromatic hydrocarbon epoxides by the microsomal fraction of rat liver.

1. The oxidation of aromatic hydrocarbons to arene oxides and the reduction of these oxides to the parent hydrocarbons are both catalysed by enzymes in the microsomal fraction of rat liver. A suggested name for the enzyme concerned in the reduction of these epoxides is 'epoxide reductase'. 2. 'Epoxide reductase' is NADPH-dependent and is inhibited by oxygen. 3. Preliminary investigations suggest that the enzyme is specific for both 'K-region' and 'non-K-region' arene oxides.

Animals↗
PubMed1975

Glutathione conjugates as metabolites of benz[a]anthracene.

1. [3H]Benz[a]anthracene is converted into water-soluble metabolites by microsomal plus soluble fractions of rat-liver in the presence of NADPH and glutathione. Chromatography on Sephadex G25 gave four radioactive peaks; the first contained hydrocarbon or hydrocarbon derivatives bound to soluble protein while the other three peaks contained glutathione conjugates of hydrocarbon metabolites. 2. Conjugates formed when either of the benz[a]anthracene metabolites, 5,6-dihydro-5,6-dihydroxybenz[a]anthracene or 8,9-dihydro-8,9-dihydroxybenz[a]anthracene, were similarly incubated were probably S-(5,6,8,9-tetrahydro-5,6,9-trihydroxybenz[a]anthracen-8-yl)glutathione and S-(5,6,8,9-tetrahydro-6,8,9-trihydroxybena[a]anthracen-5-yl)glutathione respectively. The corresponding peak obtained in the metabolism of benz[a]anthracene probably contains a mixture of these two isomers. 3. The third peak contained the conjugate, S-(5,6-dihydro-l-hydroxybenz-[a]anthracen-k-yl)glutathione, also formed by the conjugation of the "K-region" epoxide of benz[a]anthracene with glutathione. This was not formed in the metabolism of the dihydrodiols. 4. The fourth peak contained a new type of conjugate that is probably S-(8,9,10,11-tetrahydro-8,9,10-trihydroxybenz[a]anthracen-11-yl)glutathione. This conjugate is chromatographically similar to a product obtained from incubation of the 8,9-dihydrodiol, and is probably formed by microsomal oxidation of the 10,11-bond of the dihydrodiol, followed by conjugation of the resulting diol-epoxide with glutathione.

Animals↗
PubMed1966

Acetyl transfer in arylamine metabolism.

1. N-Hydroxyacetamidoaryl compounds (hydroxamic acids) are metabolites of arylamides, and an enzyme that transfers the acetyl group from these derivatives to arylamines has been found in rat tissues. The reaction products were identified by thin-layer chromatography and a spectrophotometric method, with 4-amino-azobenzene as acetyl acceptor, was used to measure enzyme activity. 2. The acetyltransferase was in the soluble fraction of rat liver, required a thiol for maximum activity and had a pH optimum between 6.0 and 7.5. 3. The soluble fractions of various rat tissues showed decreasing activity in the following order: liver, adrenal, kidney, lung, spleen, testis, heart; brain was inactive. 4. With the exception of aniline and aniline derivatives all the arylamines tested were effective as acetyl acceptors but aromatic compounds with side-chain amino groups were inactive. 5. The N-hydroxyacetamido derivatives of 2-naphthylamine, 4-amino-biphenyl and 2-aminofluorene were active acetyl donors but N-hydroxyacetanilide showed only slight activity. Acetyl-CoA was not a donor. 6. Some properties of the enzyme are compared with those of other acetyltransferases.

Acetates↗