Disulfide compound

Indeed, on heating with stannic, ferric, or antimonic chlorides in carbon disulfide, compounds 65 (R = H, Cl, or Ph R =H or Ph) afforded crystalline pyrylium salts (66) with an easily hydrolyzable... 

To deodorize a pet sprayed by a skunk, the noxious compound must be converted to an odorless one. Using an alkaline solution of 3% hydrogen peroxide and sodium bicarbonate, the thiol compound (denoted R-SH) can be oxidized to a disulfide compound,... 

Hexavalent Mo compounds absorbed appreciably, but not disulfide compounds (10, 13)... 

The cyanide nitroprusside test determines the presence of free sulfhydryl or disulfide compounds in urine samples [1, 3,4]. During the first step of the assay, cyanide reduces any disulfides that are present to free sulfhydryl compounds. In the second step, a reddish color reaction results when the free sulfhydryl groups complex with nitroprusside. A positive result is most usually due to cystine in the urine. Familial cystinuria is among the most common aminoacidurias. Disulfides are also excreted in other metabolic disorders such as homo cystinuria and ji-m e reap lol ac la le - cy s lei ne disulfiduria. Both will also produce positive results according to the following reaction RSH + Na2Fe(CN)5NO (sodium nitroprusside) — chromophore + NO. 

V Barkhold, AL Jensen. Amino acid analysis determination of cysteine plus half-cystine in proteins after hydrochloric acid hydrolysis with a disulfide compound as additive. Anal Biochem 177 318-322, 1989. 

Carbon dioxide, reduction of content of, in preparation of cyanogen, 5 44n. removal of, from commercial carbon monoxide, 6 157ra. Carbon disulfide, compound with tri-n-butylphosphine, 6 90 Carbon monoxide, 2 81 carbon dioxide removal from commercial, 6 157n. 

Latent forms of MMPs can be activated by mechanisms which cause the dissociation of the intramolecular complex between a particular cysteine residue and the required zinc metal ligand (a complex that blocks the active site) [47], This occurs because the cysteine of the latent enzyme is coordinated to the active site in a particular way that blocks the MMP active site. Collectively, the activation of MMPs occurs through a process which has been termed the cysteine-switch . Activators of the MMPs include proteases (e.g. plasmin), conformational perturbants (SDS, NaSCN), heavy metals and organomercurials (e.g. Au(I) compounds, Hg(II)), oxidants (e.g. OC1-), disulfide compounds (e.g. GSSG) and sulfhydryl alkylating agents (e.g. V-ethylmaleimide) [47 and refs, therein]. 

Title Radical Polymerization Method Performed in the Presence of Disulfide Compounds... 

Electron transfer between pyridine nucleotides and disulfide compounds is catalyzed by several fiavoproteins and three of these are well characterized. Lipoamide dehydrogenase functions in the oxidative decarboxylation of a-keto acids catalyzing the reoxidation of reduced lipoate by NAD+ (18, 19). Glutathione reductase catalyzes electron transfer between NADPH and glutathione ZO-22). Thioredoxin reductase catalyzes the reduction of thioredoxin by NADPH (5) thioredoxin is a protein of 12,000 molecular weight containing a single cystine residue which is the electron acceptor S3). 

Previously, the molecular structures of many thiuram di- [20-31] (see Fig. 1), mono- [32], trisulfides [33] and thiuram disulfide derivatives, in which R2NC(S)S- groups are linked by polymethylene chains [34], have been determined by single-crystal X-ray diffraction studies. A number of polycrystalline tetralkylthiuram disulfides and their cyclic analogs have also been recently studied by means of solid-state and CP/MAS NMR [31]. Assignments and and chemical shift data for eight (1-8) selected thiuram disulfide compounds and initial dithiocarbamate salts are shown in Table 1. The observed differences in and isotropic chemical shifts for these molecular systems can be attributed to simultaneous manifestation of the inductive effect of alkyl substituents and to the mesomeric effect of the dithiocarbamate groups discussed below. 

The apparent yield of the reaction (% acrylic acid converted to 3-mercaptopropionate) was about 1-2% at 60 C and 0.3-0.4% at 25 C. Addition of tributylphosphine, a disulfide cleaving reagent, to the reaction mixture either before ot after the 2 hour Incubation, Increased the thiol yield by about a factor of two. These results suggest that abiotic reactions may Indeed be responsible for the formation of some thiols In the environment and that thiols oxidize rapidly to form disulfide compounds even under reducing conditions. A kinetic study of the Michael reaction In seawater Is currently being undertaken. 

The following tables contain representative chemical shifts for a variety of disulfide compounds. 

However, the rearrangement of sulfides 6 is achieved by addition of catalytic amounts of hydrochloric acid at room temperature, using acetone as solvent, or thermally, by heating to 200 °C for 5 hours the yields range from 80 to 95%.9 The expected thiols can only be isolated in the form of the disulfide compounds 7. 

D-penicillamine (D-3-mercaptovaline, Cuprimine), a breakdown product of penicillin, was, after the discovery of its chelating properties of copper ion (Fig. 2-6), introduced as an antidote to copper poisoning. It was also found useful in the treatment of Wilson s disease, where excess copper accumulation causes liver cell damage. Heavy metal poisoning treatment is not limited to copper. Mercury and lead poisoning are also successfully reversed. Formation of cysteine calculi (cystinuria) can also be reversed with penicillamine by forming a soluble disulfide compound. 

F. 6.7. A disulfide bond. Covalent disulfide bonds may be formed between two molecules of cysteine or between two cysteine residues in a protein. The disulfide compound is called cystine. The hydrogens of the cysteine sulfhydryl groups are removed during oxidation. 

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