The effects of the sulfhydryl reducing agents 2-mercaptoethanol and dithiothreitol on wortmannin-induced inhibition of phosphoinositide 3-kinase (PI3K) were studied in order to examine whether the sulfhydryl reducing agents directly affect the wortmannin inhibition of PI3K. These reducing agents are commonly used to stabilize enzyme structures by maintaining protein sulfhydryl groups in the red...

The results of previous work have indicated (2, 3) that one sulfhydryl group of microsomal cytochrome reductase is essential for the interaction of nucleotides with this enzyme. These results, however, do not rule out the possibility that there are other reactive sulfhydryl groups on the native enzyme and that they are involved directly or indirectly in nucleotide-enzyme interactions. In the ex...

mehg and total mercury concentrations were determined in the muscle tissues of four fish species (cyprinus carpio, rutilus frisii, carassius auratus and esox lucius) from anzali wetland (guilan, iran). fish with the highest amount of mehg was selected to determine the thermodynamic parameters of mehg extraction. the extractions process was performed in the range of temperatures 331.15 to 367.15...

Allylsulfides from garlic are chemopreventive agents. Entering cells they are expected to initially interact with glutathione. Accordingly, reaction mechanisms of the product, S-allylthio-glutathione, with model proteins and thiols were analyzed in cell free systems. With glutathionyl, cysteinyl or captopril representing S-allyl aliphatic adducts, the reaction with sulfhydryl groups resulted in...

Changes in assisted protein folding are largely unexplored in diabetes. In the present studies, we have identified a reductive shift in the redox status of rat liver microsomes after 4 weeks of streptozotocin-induced diabetes. This change was reflected by a significant increase in the total- and protein-sulfhydryl content, as well as in the free sulfhydryl groups of the major protein disulfide ...

As a reversible posttranslational modification, protein palmitoylation has the potential to regulate the trafficking and function of a variety of proteins. However, the extent, function, and dynamic nature of palmitoylation are poorly resolved because of limitations in assay methods. Here, we introduce methods where hydroxylamine-mediated cleavage of the palmitoyl-thioester bond generates a fre...

The level of inositol phosphates was measured in rat hepatocytes treated with 2-methyl-1,4-naphthoquinone (menadione) or tert-butyl hydroperoxide, which cause Ca2+ mobilization from intracellular stores and an increase in cytosolic free Ca2+ concentration. Although neither agent produced any apparent changes in the resting level of inositol phosphates, pretreatment of hepatocytes with either me...

BACKGROUND The cyclooxygenase-2 inhibitor nimesulide is able to reduce kainate-induced oxidative stress in vivo. Here we investigate if this effect is mediated by the direct antioxidant properties of nimesulide using a well-characterized in vitro model of kainate toxicity. RESULTS Exposure of rat brain homogenates to kainate (12 mM) caused a significant (p < 0.01) increase in the concentratio...

one of the most important forms of preharvest damage to wheat is caused by sunn pests. the insects insert their mouth parts into the immature grain and while injecting their saliva suck the milky juices. flour from damaged wheat results in low baking performance due to the bug proteolytic enzymes’ injected which cause the breakdown of gluten structure in the dough. in the present study three wh...

The yellow colored sulfhydryl reagent, iV-(4-dimethylamino-3,!%dinitrophenyl)maleimide, was used in the isolation of the peptide containing the reactive sulfhydryl group of chymopapain. Titration of cyanide-activated chymopapain B with p-chloromercuribenzoate at pH 4.6 indicated that there is a maximum of 1.4 moles of sulfhydryl per mole of the enzyme. Alkylation of half of the p-chloromercurib...