stellan eriksson - Academia.edu (original) (raw)

Papers by stellan eriksson

Toxicology, 1978

Thiol agarose and glyceraldehyde-3-phosphate dehydrogenase were blocked with methylmercury or p-m... more Thiol agarose and glyceraldehyde-3-phosphate dehydrogenase were blocked with methylmercury or p-mercuribenzoate. The exchange of mercurials between the thiol-containing polymers and glutathione or dithioerythritol was investigated. The activity of glyceraldehyde-3-phosphate dehydrogenase was inhibited by blocking thiol-groups with the mercury compounds. Inhibition was reversible when a short period of inactivation was used. Inactivation for longer periods resulted in reduced regain of enzyme activity. The activity was in part regained when either of the 2 thiol compounds was added. Thioltransferase, known to catalyze thiol-disulfide exchange reactions, increased the regain of glyceraldehyde-3-phosphate dehydrogenase activity to nearly the original value. Here, thioltransferase is proposed to catalyze the transfer of organomercurial from one thiol complex to another. Some consequences of the observations in vivo are discussed.

Thioltransferase reducing mixed disulfides including thiamines, microtubuli, detoxifying proteinm... more Thioltransferase reducing mixed disulfides including thiamines, microtubuli, detoxifying proteinmercuri heavy metals and isocyanate adducts Bhopal catastrohe. Exist in isoforms

Acta Chemica Scandinavica, 1967

FEBS Letters, Mar 16, 1970

Chemischer Informationsdienst, Mar 4, 1975

Archives of Biochemistry and Biophysics, Jul 1, 1974

Rat liver supernatants were shown to contain an enzymatic activity catalyzing in both forward and... more Rat liver supernatants were shown to contain an enzymatic activity catalyzing in both forward and reverse directions the reversible sulfitolysis of glutathione disulfide. The enzymatic sulfitolysis has maximal activity at pH 7. S-Sulfoglutathione, which is a product of the sulfitolysis, was isolated by passage through an ion-exchange column. Three different assays were applied to determine S-sulfoglutathione, viz., methods based on the ninhydrin reaction, the formation of a thiazoline derivative in strong acid, and the use of radioactively labeled glutathione. The reversal of the sulfitolysis, i.e., the reaction of S-sulfoglutathione with glutathione, was studied directly by determination of sulfite with radioactive N-ethylmaleimide, or indirectly by coupling to the NADPH-and glutathione reductaselinked reduction of glutathione disulfide. Chromatographic analysis of rat liver supernatants demonstrated that all fractions catalyzing the reversible sulfitolysis did also catalyze the previously studied thiol-disulfide interchange of glutathione and the mixed disulfide of cysteine and glutathione. The reduction of thiosulfate esters, such as S-sulfocysteine and trimethylammoniumethylthiosulfate, with glutathione was also catalyzed by the enzyme active in the sulfitolysis, which indicates an important biosynthetic role of the enzyme in microorganisms synthesizing cysteine via S-sulfocysteine. The enzyme is also capable of participating in the formation of the naturally occurring S-sulfoglutathione.

Biochemical Pharmacology, 1975

Abstraet-In earlier work*, we have studied a labile enzyme activity catalyzing an exchange betwee... more Abstraet-In earlier work*, we have studied a labile enzyme activity catalyzing an exchange between thiol and acceptor. G~utathione (GSH) was used as the thiol and a number of low molecular weight substances such as cystine and GSH-disulfide derivatives, S-sulfocysteine (CySSO,H), S-sulfoglutathione and 5,5'dithiobis(2-nitrobenzoate) (DTNB) were used as acceptor substrates in the thiol transfer reaction. This broad substrate specificity led us to the tentative suggestion that thiamine disulfide derivatives also were acceptor substrates to the thioltransferaset activity, which is confirmed in this study. The methods used for the resolution ofenzymes and substrate specificity were: (1) isoelectric focusing, (2) CM-cellulose chromatography, (3) labelling of the thioltransferase with ["S]GSH, (4) gel filtration on Bio-Gel P-150, and (5) investigation of ratios of the specific activities of GSH-linked enzymes in different tissues. Generally it was found that bovine tissue had higher specific thioitransfera~ activity than rat tissue. GSH S-aryltransferase (EC 2.5.1.13) had quite different activity ratios from those obtained with the enzyme involved in cystine and thiamine disulfide reduction. This result, and dissimilar chromatographic behavior, indicate that GSH S-aryltransferase is not involved in disulfide reduction.