Sulfhydryl-disulfide Interchange Reaction Research Articles

Stimulation by insulin of cyclic AMP phosphodiesterase. role of glutathione-insulin transhydrogenase

In agreement with other workers, exposure of isolated rat fat cells to insulin shows a dose dependent increase in cyclic AMP phosphodiesterase (PDE) activity. However, when fat cells are pre-exposed to either guinea pig antiserum against insulin, rabbit antiserum against glutathione-insulin transhydrogenase (GIT), or immunogamma globulin against GIT, each antibody preparation totally or almost totally abolished the insulin-dependent increase in PDE activity. In control experiments, appropriate normal (non-immune) sera, normal gamma globulin, or the GIT-antiserum or the GIT-immunogamma globulin which had been previously neutralized with purified rat liver GIT were found to be completely ineffective in abolishing the insulin-dependent PDE activity of fat cells. These results suggest that the GIT-catalyzed sulfhydryl-disulfide inter-change reaction with insulin might be part of the mechanism by which insulin regulates the intracellular cyclic AMP concentration.

Interaction between nonsteroidal anti-inflammatory drugs and biological membranes—IV: Effects of nonsteroidal anti-inflammatory drugs and of various ions on the availability of sulfhydryl groups on lymphoid cells and mitochondrial membranes

A stimulation effect of various nonsteroidal anti-inflammatory drugs (NSAID) on a sulfhyd-ryl-disulfide interchange reaction between serum protein sulfhydryl groups and 5,5'-dithiobis-(2-nitro-benzoic) acid (DTNB) has been described. We now describe a similar reaction between 65 μM DTNB and protein sulfhydryl groups in rat, rabbit and human lymphocyte membranes and rat liver mitochondria. This reaction is greatly accelerated in the presence of ten different NSAID. The stimulation of this sulfhydryl-disulfide interchange reaction appears to be dependent on drug concentration. It is also closely related to the ionic composition of the incubation medium which, by itself, according to specific cationic and anionic sequences, influences the availability of sulfhydryl groups on membranes. The reaction of 0·6 mM carboxypyridine disulfide (CPDS), which is another molecule able to react specifically with sulfhydryl groups on membranes, is affected in a similar way by NSAID. According to the well known involvement of sulfhydryl groups in inflammatory reactions, this peculiar effect of NSAID on the availability of membrane sulfhydryl groups, especially of lymphoid cells, could be related to some of their clinical properties.

Biochemical role of glutathione on the sulfhydryl disulfide interchange reaction with randomly cross-linked ribonuclease.

An enzyme which catalyzes sulfhydryl disulfide interchange in proteins containing incorrect disulfide bonds has been reported by several investigators. In the present paper, the biological significance of glutathione on the interchange reaction to the randomly cross-linked RNase was determined. It was suggested that glutathione must be also involved in the rearrangement of the incorrect disulfide bond to form the correct disulfide bond of the corresponding native protein.

Effect of anti-arthritic drugs on sulfhydryl reactivity of rat serum.

The effect of antiarthritic drugs on a sulfhydryl-disulfide interchange reaction between rat serum sulfhydryl groups and dithiobisnitrobenzoic acid was determined. Gold sodium thiomalate and gold thioglucose produced potent, dose dependent inhibition of the interchange reaction. Thus, the interchange reaction utilizing rat serum appears to be a sensitive and quantitative procedure to measure the sulfhydryl group reactivity of potential antiarthritic agents.

Participation of the Unsymmetrical Disulfide of Coenzyme A and Glutathione in an Enzymatic Sulfhydryl-Disulfide Interchange: I. PARTIAL PURIFICATION AND PROPERTIES OF THE BOVINE KIDNEY ENZYME

Abstract An enzyme that catalyzes the following sulfhydryl-disulfide interchange reaction has been purified 180-fold from bovine kidney. GSH + CoASSG ⇌ GSSG + CoA-SH In addition, it has been detected in most rat tissues studied. Its pH optimum is 8.2 and the equilibrium constant for the reaction is near unity at pH 6.9 and 25°. Michaelis constants for reduced glutathione and CoASSG are 3.3 x 10-4 m and 4.5 x 10-5 m, respectively. The molecular weight of the enzyme, determined by gel filtration, is approximately 12,000. Several unsymmetrical disulfides containing a glutathione residue are equally as effective as substrates. The enzyme, which becomes less active during storage, is largely reactivated by GSH. Its potential physiological significance is discussed.

INFLUENCE OF HYDRALAZINE ON THE SULFHYDRYL GROUP IN THE PRESENCE OF CUPRIC ION.

SummaryFifty-one compounds were studied for their ability to compete with the sulfhydryl group for cupric ions. The sulfhydryl-disulfide interchange reactions occurring during the reaction between cysteine and bis (p-nitrophenyl) disulfide and during the course of the denaturation of human serum gamma globulin by heat were used as models for this reaction. Hydralazine, a compound which has been reported to induce a disease resembling systemic lupus erythematosus was exceptionally active in reactivating the sulfhydryl-disulfide interchange reaction when this reaction was studied in the presence of cupric ion.

The effect of N-acetylcysteine on theviscosity of tracheobronchial secretions in cystic fibrosis of the pancreas

N-acetylcysteine reduces the viscosity of tracheobronchial secretions apparently through a specific sulfhydryl-disulfide interchange reaction. Additional mucolysis is achieved by its salt effect on the desoxyribonucleic acid (DNA) present. Pulmonary diseases in which the viscosity of tracheobronchial secretions is responsible for their pathophysiology may be benefited by nebulization of concentrated solutions of N-acetylcysteine. Viscosity measurements were determined on secretions obtained per tracheostomy from 2 patients with cystic fibrosis with the use of N-acetylcysteine as an aerosol. N-acetylcysteine produced a greater fall in the viscosity of the secretions than did 2 control aerosols.

The Effects of Iodination and Related Modifications on the Supercontraction of Wool Fibers

Iodination of wool fibers in ethanol or n-propanol accelerates the first stage and retards the second stage of supercontraction. Iodination in aqueous KI3 has little effect on the rate of the first stage but retards the second stage of supercontraction. Evidence is presented that the rate of supercontraction is affected by at least two chemical processes which occur during iodination in ethanol : oxidation of sulfhydryl and disulfide groups, and the reaction of ethanol with the fiber in the presence of HI with consequent esterifica tion of carboxyl groups. Oxidative treatments, such as reaction with peracetic acid, aqueous KI3, or ethanolic I2 are considered to retard sulfhydryl-disulfide interchange reactions which determine the rate of the second stage of supercontraction.