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Biomedical subjects

E Boyland

Publications and source records attributed to E Boyland.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1967

The effect of pretreatment with adrenal-protecting compounds on the metabolism of 7,12-dimethylbenz[a]anthracene and related compounds by rat-liver homogenates.

1. 7,12-Dimethylbenz[a]anthracene is converted by rat-liver homogenates into products with the properties of the 7- and 12-hydroxymethyl derivatives, the 7,12-dihydroxymethyl derivative, the related carboxylic acids and ring-hydroxylated products such as the 8,9-dihydro-8,9-dihydroxy derivative and phenols. Ring-hydroxylated products and products arising from the further oxidation of the hydroxymethyl groups were formed when the hydroxymethyl derivatives were themselves incubated with rat-liver homogenates. 2. Pretreatment of the animal with 3-methylcholanthrene or with Sudan III, which can protect rat adrenal glands from damage by 7,12-dimethylbenz[a]anthracene or by its 7-hydroxymethyl derivative, led to an increased rate of metabolism of 7,12-dimethylbenz[a]anthracene and its hydroxymethyl derivatives. The metabolic routes mainly affected were those involving the formation of ring-hydroxylated products. 3. Pretreatment with phenobarbitone led to a small increase in the rate of metabolism of the hydrocarbon and of its hydroxymethyl derivatives, but the increase appeared mainly to involve increased metabolism of the methyl and hydroxymethyl groups. 4. Pretreatment with metyrapone increased the rate of metabolism of the hydrocarbon mainly by increasing the amounts of products resulting from hydroxylation of the methyl groups: small increases in the amounts of ring-hydroxylated products were also produced. 8. Of a number of hydrocarbons and of derivatives of 3-methylcholanthrene tested as enzyme inducers, 3-methylcholanthrene itself was the most effective.

Adrenal Glands↗
PubMed1966

The biochemistry of aromatic amines. 2-Formamido-1-naphthyl hydrogen sulphate, a metabolite of 2-naphthylamine.

1. 2-Formamido-1-naphthyl hydrogen sulphate is excreted by dogs and rats dosed with 2-naphthylamine or with 2-amino-1-naphthyl hydrogen sulphate and was isolated from dog urine. 2. 2-Formamido-1-naphthol, naphtho[2,1-d]oxazole and N-formyl-2-naphthylhydroxylamine are excreted as (2-formamido-1-naphthyl glucosid)uronic acid. 2-Formamidonaphthalene is converted into conjugates of 2-amino-6-naphthol and 2-amino-8-naphthol, but 2-methylaminonaphthalene is excreted as 2-amino-1-naphthyl hydrogen sulphate and its N-methyl and N-formyl derivatives and (2-amino-1-naphthyl glucosid)uronic acid. 3. 2-Methylamino-1-naphthyl hydrogen sulphate is converted into 2-formamido-1-naphthyl hydrogen sulphate and 2-amino-1-naphthyl hydrogen sulphate on charcoal. 2-Amino-1-naphthyl hydrogen sulphate and formaldehyde react on charcoal to yield 2-methylamino- and 2-formamido-1-naphthyl hydrogen sulphate. 4. 2-Formamido-1-naphthol, 2-formamido-1-naphthyl hydrogen sulphate, N-formyl-2-naphthylhydroxylamine and N-formyl-2-naphthylhydroxylamine-O-sulphonic acid were synthesized.

Animals↗
PubMed1966

The biochemistry of aromatic amines. The metabolism of 2-naphthylamine and 2-naphthylhydroxylamine derivatives.

1. 2-Naphthylhydroxylamine and 2-nitrosonaphthalene were present in urine of dogs but not of guinea pigs, hamsters, rabbits or rats dosed with 2-naphthylamine. N-Acetyl-2-naphthylhydroxylamine and its O-sulphonic acid and O-glucosiduronic acid were not detected in the urine of any of these species. 2. Bile from rats dosed with 2-naphthylamine contained (2-naphthylamine N-glucosid)uronic acid and 6- and 5,6-substituted derivatives of 2-acetamidonaphthalene. 2-Amino-1-naphthyl and 2-acetamido-1-naphthyl derivatives, 2-naphthylhydroxylamine and its N-acetyl derivative or conjugates of these were not detected. Bile from a dog dosed with 2-naphthylamine contained no 2-amino-1-naphthyl derivatives. 3. 2-Naphthylhydroxylamine was metabolized by the dog, rat and guinea pig to the same products as those formed by these species from 2-naphthylamine. Rabbits formed mainly 2-amino-1-naphthyl derivatives; these are minor metabolites of 2-naphthylamine in this species. 4. (N-Acetyl-2-naphthylhydroxylamine O-glucosid)uronic acid was excreted in the urine and the bile of rats and in the urine of guinea pigs and rabbits dosed with N-acetyl-2-naphthylhydroxylamine. 5. After the administration of 2-acetamidonaphthalene, (N-acetyl-2-naphthylhydroxylamine O-glucosid)uronic acid was detected in the urine of dogs, but not in the urine of other species. The dog excreted an acid-labile cysteine derivative of 2-acetamidonaphthalene, but only traces of the corresponding mercapturic acid. 6. After dosing with N-acetyl-2-naphthylhydroxylamine-O-sulphonic acid, rats excreted derivatives of 2-amino-1-naphthol. 7. 2-Nitrosonaphthalene, N-acetyl-2-naphthylhydroxylamine, N-acetyl-2-naphthylhydroxylamine-O-sulphonic acid, 2-naphthylhydroxylamine-N-sulphonic acid, N-benzyloxycarbonyl-2-naphthylhydroxylamine and N-benzyloxycarbonyl-2-naphthylhydroxylamine-O-sulphonic acid were synthesized.

Animals↗