William B. Jakoby

William B. Jakoby
National Institutes of Health | NIH

PhD

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199
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Publications

Publications (199)
Article
The initial enzymic step in mercapturic acid formation is catalyzed by glutathione S-transferase. Several species of this enzyme, designated as transferases α. β, γ, δ and e an the basis of increasing isoelectric points, were isolated from human liver. Evidence is presented that each of the purified species is homogeneous with respect to sodium dod...
Article
The sulfotransferases that are active in the metabolism of xenobiotics represent a large family of enzymes that catalyze the transfer of the sulfuryl group from 3'-phosphoadenosine 5'-phosphosulfate to phenols, to primary and secondary alcohols, to several additional oxygen-containing functional groups, and to amines. Restriction of this review to...
Article
Aryl sulfotransferase IV from rat liver has the very broad substrate range that is characteristic of the enzymes of detoxication. With the conventional assay substrates, 4-nitrophenol and PAPS, sulfation was considered optimal at pH 5.5 whereas the enzyme in the physiological pH range was curiously ineffective. These properties would seem to preclu...
Article
Full-text available
Ethylene carbonate, a cyclic organic carbonate widely used industrially, is toxic when metabolically converted to ethylene glycol. A rat liver enzyme active in catalyzing the ring opening has been purified to electrophoretic homogeneity and found to be active in the hydrolysis of ethylene, vinylene, and propylene carbonates to CO2 and the respectiv...
Article
Aryl sulfotransferase IV from rat liver has the broad substrate range that is characteristic of the enzymes of detoxication. With the standard assay substrates, 4-nitrophenol and 3'-phosphoadenosine 5'-phosphosulfate (PAPS), sulfation is optimum at pH 5.4 whereas the reaction is minimal in the physiological pH range. These properties preclude a phy...
Article
Aryl sulfotransferase IV from rat liver has the broad substrate range that is characteristic of the enzymes of detoxication. With the standard assay substrates, 4-nitrophenol and 3′-phosphoadenosine 5′-phosphosulfate (PAPS), sulfation is optimum at pH 5.4 whereas the reaction is minimal in the physiological pH range. These properties preclude a phy...
Article
Full-text available
Oxidation at Cys66 of rat liver aryl sulfotransferase IV alters the enzyme's catalytic activity, pH optima and substrate specificity. Although this is a cytosolic detoxication enzyme, the pH optimum for the standard assay substrate 4-nitrophenol is at pH 5.5; upon oxidation, the optimum changes to the physiological pH range. The principal effect of...
Article
A phenol sulfotransferase from rat liver (EC 2.8.2.9), expressed in Escherichia coli from a single cDNA, was purified as two separable but catalytically active proteins. The proteins appeared to be identical to each other and to the natural liver sulfotransferase by comparison of their amino acid constitution, amino-terminal end group, and interact...
Article
Elhylcnc carbonate, a compound widely used in industry, is lethally toxic to the central nervous system and kidney because of its metabolic conversion to ethylene glycol. A rat liver enzyme active in the hydrolysis of this cyclic carbonate bus now been purified to homogeneity and found to catalyze the reaction shown: n o'(\> OH OH l; y + H-4° -4-4...
Article
The over-expression of mammalian enzymes in bacterial systems by means of recombinant DNA technology has provided the enzymologist with a supply of catalyst sufficiently abundant to identify suboptimal substrates. Such large quantities are particularly useful when working with the enzymes of detoxication, a family of proteins that are distinguished...
Article
Full-text available
Imidase, an enzyme variously identified as dihydropyrimidinase (EC 3.5.2.2), hydantoinase, dihydropyrimidine hydrase, and dihydropyrimidine amidohydrolase, has been purified to electrophoretic homogeneity from rat liver. Although a component in the chain of pyrimidine catabolism, imidase is capable of serving in a broader role that includes detoxic...
Article
A nucleotide sequence that had been proposed for, but not identified as, rat liver aryl sulfotransferase (EC 2.8.2.1) was prepared in an appropriate vector and transformed intoEscherichia coli. The protein, expressed in large amounts, was not aryl sulfotransferase (EC 2.8.2.1) but rather tyrosine-ester sulfotransferase (EC 2.8.2.9), a sulfotransfer...
Article
An effort to identify the major general esterases of rat liver cytosol that are insensitive to the serine esterase inhibitor paraoxon (diethyl 4-nitrophenyl phosphate) has led to the isolation of a dozen enzymes. Four of these are electrophoretically homogeneous. Although purified on the basis of their hydrolytic activity toward 4-nitrophenyl aceta...
Article
Unlike most esterases, which are predominantly bound to the microsomal fraction, the enzymes hydrolyzing acetylsalicylic acid are present in an equal amount in the cytosol. Two soluble isozymes were purified to homogeneity from rat liver and characterized as serine esterases with a Mr of 35,000. Both had the wide substrate spectrum characteristic o...
Article
Catalytic activities of two amine N-methyltransferases were documented for the following azaheterocycles: isomeric phenyl- and bispyridyls; 2-, 3- and 4-mono-substituted pyridines; and a miscellaneous group of azaheterocycles that included mono- and diazabenzenes and mono- and diazanaphthalenes. The broad substrate specificities of the two amine N-...
Article
Results of in situ immunohistochemical investigations on several enzymes which participate in the bioactivation and detoxication of xenobiotics and of histochemical studies on aryl hydrocarbon hydroxylase activity summarized in this report clearly demonstrate that there are numerous sites within the respiratory tract at which xenobiotics can be bio...
Article
Full-text available
Two amine N-methyltransferases isolated from rabbit liver catalyze S-adenosylmethionine-dependent N-methylation of benzidine and 4-aminobiphenyl but not of 4-aminoazobenzene or 2-aminobiphenyl. The enzymatic reaction products were analyzed and found to be identical to synthetic N-methylbenzidine and N-methyl-4-aminobiphenyl. N-Methylation may be a...
Book
This book contains 76 chapters. Some of the titles are: Nucleus, DNA, and chromatin; Hepatic gene expression and mRNA metabolism; Protein synthesis and gene control in pathophysiologic states; and hormonal control of gene expression.
Article
Full-text available
A highly purified amine N-sulfotransferase has been isolated from guinea pig liver that catalyzes sulfuryl group transfer from 3'-phosphoadenosine 5'-phosphosulfate to one of a large number of either primary or secondary amines forming the appropriate sulfamate and adenosine 3',5'-bisphosphate. Amines as different as aniline, 2-naphthylamine, octyl...
Article
Full-text available
(2')3',5'-Bisphosphate nucleotidase has been prepared in electrophoretically homogeneous form from guinea pig liver. The enzyme catalyzes the hydrolysis of the 2'- or 3'-phosphate from the appropriate nucleoside 2',5'- and 3',5'-bisphosphates and is active with 3'-phosphoadenosine 5'-phosphosulfate and with coenzyme A but not with ATP. The 40,000-d...
Article
This chapter discusses the sulfotransferase assays. The sulfotransferases for which assays are presented are those capable of transferring the sulfuryl group, SO3, from 3'-phosphoadenylylsulfate (or 3'-phosphoadenosine 5'-phosphosulfate, abbreviated PAPS) to a compound of small molecular mass bearing a hydroxyl or amino group. The products are aden...
Article
Amine N-methyltransferases in the brains of humans, monkeys, mice, rabbits and rats, as well as two homogeneous enzymes isolated from rabbit liver, are capable of N-methylating 4-phenyl-1,2,3,6-tetrahydropyridine to 1-methyl-4-phenyltetrahydropyridine (MPTP), and 4-phenylpyridine to 1-methyl-4-phenylpyridinium ion (MPP+). The product in each instan...
Article
The substrate specificity of two homogeneous amine N-methyltransferases from rabbit liver has been demonstrated to extend to the azaheterocycles pyridine, R-(+)-nicotine and S-(-)-nicotine. Both enzymes methylate R-(+)-nicotine at the pyridyl nitrogen to afford the N-methylnicotinium salt, whereas S-(-)-nicotine does not act as a substrate for eith...
Article
Full-text available
N-Methylation of amines has been ascribed to enzymes listed as amine N-methyltransferase, indolethylamine N-methyltransferase, and arylamine N-methyltransferase. All of these activities are accomplished by each of two related enzymes present in rabbit liver. The two N-methyltransferases have a very broad and overlapping specificity for primary and...
Article
Results of immunohistochemical and histochemical investigations on xenobiotic-metabolizing enzymes and aryl hydrocarbon hydroxylase activity have demonstrated that xenobiotic activation and detoxication do not occur uniformly throughout the liver, skin, respiratory tract, and pancreas, four tissues that are targets for the toxic actions of xenobiot...
Article
The cysteine conjugate β-lyase enzyme is effective with thioethers of cysteine and with derivatives of alanine bearing a good leaving group at the β-carbon. The β-1yase represents the initial enzyme in a shunt pathway from mercapturic acid synthesis; that also includes thiol S-methyltransferase. Two assay methods for this enzyme are discussed in th...
Article
This chapter provides an overview of the glutathione transferases. They are among the catalysts that participate in the process of detoxication, the means by which those compounds without nutritional value are eliminated, usually after metabolic processing. The glutathione transferases are normally present in large quantities, representing about 10...
Article
Cysteine S-conjugate N-acetyltransferase from rat kidney microsomes catalyzes the final reaction in mercapturic acid biosynthesis, the acetylation of cysteine thioethers. This enzyme is not active with substrates of the cytosolic amine N-acetyltransferase. The transfer of a radiolabeled acetyl group from CoASAc to a cysteine conjugate is used as th...
Article
Full-text available
2-Propylthiouracil has been reported as replacing glutathione as a substrate for the glutathione transferases of rat liver. This observation has been examined with several homogeneous glutathione transferases that were prepared from human and rat liver by different methods in three laboratories. No evidence was obtained for 2-propylthiouracil as a...
Article
Cysteine conjugate beta-lyase from rat liver, an enzyme participating in a shunt from mercapturic acid synthesis, has been purified and found to be active with a number of compounds that bear nonpolar leaving groups on the beta-carbon of an amino acid substrate. Pyridoxal phosphate is considered to be a participant in the reaction. In addition to a...
Article
Full-text available
Sheep antibodies raised against three isoenzymes of glutathione S-transferase (EC 2.5.1.18), transferases B, C, and E, which were isolated and purified to apparent homogeneity from rat liver, have been employed to localize these enzymes at the light microscopic level within livers of untreated rats. Using these antibodies in an unlabeled antibody p...
Article
Five enzymes, active in the transfer of a methyl group to either oxygen, nitrogen or sulfur atoms, were inhibited competitively by a peptide isolated from rabbit liver. The peptide, named methinin, appears to have a chromophore that resembles pyridinoline, a cross linking amino acid found in elastin and collagen.
Article
Full-text available
Arylamine N-methyltransferase catalyzes the novel methylation of the ring nitrogen of tryptamine and pyrrole as well as a number of other arylamines including aniline and its derivatives. S-Adenosyl-L-methionine serves as donor. Tyramine, indole, benzylamine, and desmethylimipramine were inactive as methyl group acceptors. The enzyme was purified f...
Article
. Dehydrogenase activity with hydroxysteroids has been observed in Tetrahymena furgasoni (formerly T. pyriformis strain W), and the enzyme responsible has been isolated from this organism. The purified dehydrogenase is active with a variety of steroid alcohols at apparent Km values ranging from 0.2 to 4.0 mM. The C-3 hydroxyl of ring A of the stero...
Article
An acetyltransferase from rat kidney microsomes that catalyzes the N-acetylation of thioethers of L-cysteine has been solubilized, stabilized, and separated from hydrolytic enzymes active against both the acetylated product, a mercapturic acid, and acetyl coenzyme A. Efficiency of catalysis varies with the lipophilicity of the substituent at sulfur...
Chapter
A wide range of amines is known to be methylated in reactions catalyzed by mammalian enzymes with S-methyl-L-adenosine as the methyl donor. The observation of a system of low substrate specificity in extracts of rabbit lung by Axelrod and its reported distribution (Axelrod, J., 1962, Saavedra, J.M., et. al., 1973, Borchardt, R.T., 1980), suggested...
Article
Full-text available
Aryl sulfotransferase IV (EC 2.8.2.1), purified to homogeneity from male rat liver, catalyzes the sulfation of a variety of substituted phenols, including catecholamines, tyrosine esters, and peptides containing NH2-terminal tyrosine residues. An investigation of the mechanism of the enzyme was carried out using 2-chloro-4-nitrophenol as a model su...
Article
A group of aryl sulfotransferases has been identified that catalyzes sulfate ester formation with simple phenols at an acidic pH and with several physiological metabolites at a more alkaline pH. One enzyme, aryl sulfotransferase IV, has been purified to homogeneity and found to be a protein of 61,000 daltons composed of two subunits of apparent equ...
Article
The transfer of sulfate to thyroid hormones and their analogs by a monkey hepatocarcinoma cell extract was compared to this reaction as catalyzed by two homogeneous aryl sulfotransferases from rat liver. The thyroid hormones 3,5,3'-triiodo-L-thyronine and L-T4 as well as analogs of these hormones, were used as substrates. While these compounds vary...
Article
Publisher Summary This chapter provides the spectrophotometric, titrimetric, nitrite, and cyanide assay for the differentiation of glutathione S-transferases. Spectrophotometric assays depend upon a direct change in the absorbance of the substrate when it is conjugated with glutathione (GSH). Because each of the reactions is catalyzed at a finite r...
Article
Aryl Sulfotransferases are a group of enzymes that are active with a wide variety of phenolic compounds as substrates. The aryl sulfotransferases fall into two families. The first family consists of aryl sulfotransferases I and II. Second family comprises of aryl sulfotransferases III and IV, which also resemble each other in their specificity for...
Article
Thiol S-methyltransferase is present in liver microsomes and it can be solubilized and partially purified by use of detergents. This chapter describes a procedure for enzyme from the rat liver that provides a homogeneous protein without the use of detergents in the solubilization process. Thiol S-methyltransferase activity is determined by measurin...
Article
This chapter presents a procedure for the preparation of arylamine N-methyltransferase. The assay depends on the highly radioactive, methyllabeled—S-adenosylmethionine—which is readily available commercially. Tryptamine serves as the methyl group acceptor in the standard assay. After reaction, the methylated product is separated from the polar radi...
Article
This chapter presents a procedure for homogeneous preparations of hydroxysteroid sulfotransferase. The assays for hydroxystcroid sulfotransferase are based on the separation of radiolabeled substrate from product on the basis of polarity. A filter method, using radiolabeled steroid as substrate, is simple, rapid, and effective for enzyme purificati...
Article
Publisher Summary This chapter presents a procedure for the preparation of glutathione transferases of the rat and the human. The glutathione S-transferases are the enzymes catalyzing conjugation reactions with glutathione as the first step in mercapturic acid synthesis. Although these enzymes may be distinguished from each other by their character...
Article
Hepatic cytosolic glutathione transferase activity with 1-chloro-2,4-dinitrobenzene as substrate was induced by 3-methylcholanthrene or β-naphthoflavone in C57BL/6N inbred mice and in (C57BL/6N)(DBA/2N)F 1 but not in DBA/2N inbred mice. High doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin induced the transferase activity in both C57BL/6N and DBA/2N mi...
Article
The major hydroxysteroid sulfotransferase found in the livers of female rats has been purified to homogeneity and found to catalyze the transfer of sulfate to any of several hydroxysteroids including dehydroepiandrosterone, estradiol, testosterone, and androstenediol thus forming the corresponding sulfate esters. 3′-Phosphoadenosine 5′-phosphosulfa...
Article
Hydroxysteroid sulfotransferase 1, an enzyme effective in the transfer of sulfate from adenosine 3′-phosphate-5′-phosphosulfate to a wide variety of hydroxysteroids, was purified to homogeneity from rat liver. The protein is 180,000 daltons with subunits of 28,000 daltons. The actual specificity of the enzyme is not limited to hydroxysteroids. Rath...
Article
The thiol S-methyltransferase from rat liver has been solubilized and prepared in homogeneous form. The enzyme exists in a monomer of Mr 28,000 although enzyme activity is highly unstable with a half-life of 4 days under the best conditions of storage. The reaction requires S-adenosylmethionine as methyl donor but, as is the case with many enzymes...
Article
Full-text available
Two phenol sulfotransferases have been purified from rat liver by conventional techniques coupled with affinity chromatography on Affi-Gel blue and ATP-agarose. Both enzymes are homogeneous by the criterion of sodium dodecyl sulfate gel electrophoresis. Each enzyme has a molecular weight of approximately 65,000 and consists of two subunits of appar...
Article
Two methods are described for the assay of sulfotransferases which are active with sulfate acceptors bearing the hydroxyl functional group. Assays were developed for enzymes which transfer sulfate from 3′-phosphoadenosine–5′-phosphosulfate (PAPS) to sterols, phenols, and simple alcohols thereby forming the corresponding sulfate esters. With a filte...
Article
A convenient method is presented for quantitating disulfide interchange reactions based on the use of a commercially available organomercurial resin. Isotopically labeled thiol is incubated with a disulfide and the reaction is terminated by charging the incubation mixture onto the resin. The thiol is bound as the mercaptide allowing labeled interch...
Article
Full-text available
Homogeneous preparations of the glutathione transferases from rat liver have been tested for their ability to catalyze a number of diverse nucleophilic reactions of GSH. Although disulfide interchange with GSSG or L-cystine, and cis-trans isomerization of maleic acid, are clearly promoted by thiols in solution, the reactions were not catalyzed by t...
Article
Glutathione transferase ϱ has been purified to homogeneity from human erythrocytes. The enzyme has a molecular weight of 47,500 and is composed of two subunits of the same apparent molecular weight. The enzyme is active in catalyzing the reaction of glutathione, as a nucleophile, with a variety of compounds bearing an electrophilic center. Thioethe...
Article
Glutathione transferase ρ{variant} has been purified to homogeneity from human erythrocytes. The enzyme has a molecular weight of 47,500 and is composed of two subunits of the same apparent molecular weight. The enzyme is active in catalyzing the reaction of glutathione, as a nucleophile, with a variety of compounds bearing an electrophilic center....
Article
Full-text available
After the intravenous injection of unconjugated [(3)H]bilirubin into normal Sprague-Dawley and Wistar R rats, radiolabeled bile pigments rapidly accumulated in the liver. By 1.5 min after injection, an average of 36% of the injected isotope was present in liver homogenates. Between 3 and 15 min, 37-64% of the total intrahepatic radiolabeled bilirub...
Article
The physiological roles of the glutathione S-transferases, by whatever name, seem to result in detoxification. As is true of albumin, members of this group of proteins bind an enormous number of compounds that appear to have in common only hydrophobic topography; the binding of bilirubin is an example of a major function common to all higher specie...
Article
Because the glutathione S-transferases perform a detoxification function in liver and kidney, evidence for them was sought in the intestine, another major site of contact with xenobiotics. The range of activity with several different substrates was similar to that of liver: highest activity was observed with 1-chioro-2,4-dinitrobenzene. Antibodies...
Article
The glutathione transferases (EC 2.5.1.18) appear to perform several detoxification functions. This group of enzvmes is analogous to serum albumin in the broad spectrum of compounds that serve as ligands, but differs significantly in that the transferases have an additional and specific site for GSH. They appear to catalyze all reactions that would...
Article
As well as being catalysts of several different types of reactions, the glutathione S-transferases also act as storage proteins and, in time of need, undergo covalent linkage with highly reactive electrophilic compounds.
Article
Soluble, glutathione-stimulated delta 5-3-ketosteroid isomerase (EC 5.3.3.A) activity of human and rat liver resides in very basic proteins with molecular weights of about 45,000 which are present in high concentrations in these tissues. Physiochemical and immunological evidence is presented for the identity of the proteins responsible for this enz...
Article
Full-text available
The catalyzed reactions of GSH with organic nitrate and thiocyanate esters and with a series of chloronitrobenzene substrates have been investigated and the results used to formulate a mechanism for glutathione S-transferase catalysis. All the homogeneous preparations of the glutathione transferases that have been tested catalyze the reaction of GS...
Article
Glutathione S-transferase AA from rat liver was purified to apparent homogeneity as judged by gel filtration and gel electrofocusing. The protein has an isoelectric point near pH 9.9 and a molecular weight of 45,000 and is composed of two apparently identical subunits. The enzyme is most active with 1-chloro-2,4-dinitrobenzene and glutathione as su...
Article
The initial enzymic step in mercapturic acid formation is catalyzed by glutathione S-transferase. Several species of this enzyme, designated as transferases alpha, beta, gamma, delta and epsilon on the basis of increasing isoelectric points, were isolated from human liver. Evidence is presented that each of the purified species is homogeneous with...
Article
Full-text available
Fluorescence spectroscopy and inhibition kinetics were used to quantitate the affinity of nonsubstrate ligands for the rat liver glutathione S-transferases AA, A, B, and C in the presence of glutahione. The dissociation constants KD, for ligands such as bilirubin, indocyanine green, and hematin were determined by measuring the decrease in the intri...
Article
WE report direct evidence that conjugation with glutathione (GSH) is a significant mechanism for detoxification of the epoxides of polycyclic aromatic hydrocarbons. We believe that the level of the enzymes may be directly relevant to the carcinogenic potential of the hydrocarbons, which are common pollutants1. They are metabolised by microsomal mix...
Article
Evidence is presented that glutathione S-transferases, a group of enzymes active in the formation of thioethers from glutathione and a large number of compounds with an electrophilic carbon atom, can also catalyze the formation of nitrous acid and oxidized glutathione from organic nitrate esters such as nitroglycerin. In addition, organic thiocyana...

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