Glutathione cysteine and

Chemiluminescence has been observed during the oxidation of these compounds by molecular oxygen in the presence of heavy metal catalysts. Copper-II-compounds ([Cu (NH3)4] + and a Cu- flavin mononucleotide complex) were found to be especially efficient. The emitting species seems to be singlet oxygen in both cases. The emission is accompanied by FMN fluorescence [52]. 

The singlet oxygen may be formed from the superoxide anion produced by a one-electron transfer from the sulfur atoms of cysteine or glutathione, respectively. The products are the corresponding disulfides. The one- electron transfer appears to take place in the coordination sphere of e.g. the copper-II ions, according to spectroscopic evidence. 

Another chemiluminescent system containing copper-II- ions, riboflavin, hydrogen peroxide, and mercaptoethanol [53] appears to proceed via a similar mechanism, H02 radicals being intermediates. 

Berlman, I. B., Handbook of Fluorescence Spectra of Aromatic Compounds Academic Press N. Y. 1971 

Shlyapintokh, V. Ya., Chemiluminescentnye Metody Issledovania Medlennych Chimiceskich Processov, p. 158, 1960 

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Showdomycin inhibits synthesis of nucleic acid. Thiols, such as cysteine and glutathione (among other compounds), reverse this inhibition, and it is considered that the interaction of the maleimide moiety with sulfhydryl groups within the cell or in the membrane may be responsible for the selective inhibition of enzymes by show-... 

Gruetter, C. A., Lemke, S. M., Dissociation of cysteine and glutathione levels from nitroglycerin-induced relaxation. 

The decomposition mode of the adducts has early been noticed to be associated with redox reactions (60,77), and is currently under scrutiny because of its great bioinorganic relevance. It has been shown that the reduction of NP to the EPR-active [Fe(CN)5NO]3 ion occurs in the reaction with cysteine, which is oxidized to cystine (60). In this reaction, NP showed to behave catalytically with respect to the autoxidation of cysteine to cystine, provided enough oxygen was present. A recent kinetic and mechanistic study has thrown more light on the complex mechanistic details comprising the decompositions of the red adducts formed by NP with cysteine, A-acetylcysteine, ethyl cysteinate, and glutathione (120). Under conditions of excess of NP, in anaerobic medium, the reversible adduct formation step is shown by Eq. (26) ... 

An HPLC method was developed and validated for the determination and quantitation of both DFC cysteine and glutathione conjugates. This method was based on a cleavage of the disulphide and/or thioester bonds between the metabolites and their conjugate sulphur-containing moiety using dithioerythritol to yield DFC, which was then stabilized by derivatizing to DFC acetamide (91). 

It is of note that alkaline and acid phosphatase exhibit no silikatase activity. Divalent sulfur-containing compounds, such as sulfide, methionine, cysteine and glutathione have a positive effect on silica uptake536) also water temperature and silica concentration in the aqueous phase control the Si-cycle in cellular systems529-531, 53 ). 

T6. Tsakiris, S., Angelogianni, P, Schulpis, K. H., and Behrakis, P., Protective effect of L-cysteine and glutathione on rat brain Na+,K+-ATPase inhibition induced by free radicals. Z. Naturforsch. 55c, 271-277 (2000). 

Thiol methyltransferase has been detected in erythrocytes, lymphocytes, lungs, cecal, and colonic mucosae. The nature and number of thiol methyltransferases is not clear at the present time. A cytosolic enzyme and a microsomal enzyme have been reported, with the microsomal enzyme being dissociated from membrane relatively easily. The microsomal enzyme in rat liver has been purified to homogeneity. The enzyme is a 28,000-dalton monomer with an isoelectric point of 6.2. A wide variety of xenobiotic thiols are methylated, but cysteine and glutathione are not substrates. S-Methylation is an important component in the thiomethyl shunt. Thiomethyl conjugates are metabolized to the methylsulfoxides by oxidation (see Chapter 10) and reenter the mercapturic acid pathway as substrates for glutathione S-transferase. 

Zhang, Y., Chien, M., Ho, C. T. (1988). Comparaison of the volatile compounds obtained from thermal degradation of cysteine and glutathione. J. Agric. Food Chem., 36, 992-996. 

J.Vina, M. Vento, F. Garcia-Sala, 1. Purtes, E. Gasco, J. Sastre, M. Asensi and V. Pallardo, L-Cysteine and Glutathione Metabolism Are Impaired in Premature Infants due to Cystathionase Deficiency, Am J Clin Nutr 61 (1995) 1067-1069. 

Dormann, P., Botchers, X, Korf, U Hojrup, P., Roepstorff, F, and Spencer, F. (1993). Amino acid exchange and covalent modification by cysteine and glutathione explain isoforms of fatty acid-binding protein occurring itt bovine liver. /. Bib . Cfiem. 268,16286 8292. 

Halbert, M.K. Baldwin, R.P. Determination of cysteine and glutathione in plasma and blood by liquid chromatography with electrochemical detection using a chemically modified electrode containing cobalt phthalocyanine. J. Chromatogr. 1985, 345, 43 9. 

Albumin is responsible for the largest fraction of free sulfhydryl (Cys-34) in blood serum, and studies have shown that it is also the most reactive sulfhydryl. The chemical reactivity of Cys-34 is reported to have an unusually low p sH of 5 compared with 8.5 and 8.9 for cysteine and glutathione, respectively (Pedersen and Jacobsen, 1980). In most preparations of albumin, 30-35% of Cys-34 is occupied by cysteine or glutathione. Blocking of Cys-34 with cysteine, glutathione, or other chemicals such as A-idosuccinimide stabilizes albumin against dimer formation (Peters, 1985). Presumably, Cys-34 plays a direct or catalytic role in this process. 

It has been known previously that substances which oxidize readily, such as ascorbic acid, are reduced in the aged 141) and that the use of antioxidants such as Vitamin E and selenium compoimds can inactivate free radicals 142). It also has been observed that agents which bind ultratrace metals, particularly protein-rich sulfahydryl groups such as cysteines and glutathione have the capability of neutralizing the eflFect of free radicals 140). 

Sodium enolates of ketones and disodium enediolates of substituted phenylacetic acids reacted with activated aziridines to afford 7-amido ketones and 7-amidobutyric acids, respectively (Scheme 72). Aziridine-2-carboxylic acid esters can be utilized as versatile precursors for amino acid derivatives. Although the product distribution resulting from the reaction of activated aziridine-2-carboxylates with amines depends on the structure of the reactants, the reactions with alcohols or thiols in the presence of acidic cabilysts generally gave the a-amino acid derivatives (Scheme 73). ° On the other hand, free 3-methyl-2-aziridinecarboxylic acids (168) reacted with thiophenol, cysteine and glutathione to afford P-amino acid derivatives with sulfur substituents at the a-position as the main product (Scheme 73). ... 

The Vra complex with L-cysteine was prepared and characterized the crystal structure shows a 1 2 stoichiometry and that the two S-donors are trans to one another while the O- and N-donors are cis to one another (194).810 With three different donor functionalities, this 1 2 complex illustrates key aspects of Vm coordination chemistry. To identify the mode of action of cellular vanadium species and the roles of cysteine and glutathione in cellular redox chemistry, the redox and complexation chemistry of vanadium with sulfur-containing ligands must be better... 

Evidence for the activity of some radioprotectors as inhibitors of free radical processes has appeared, and the subject has been reviewed Involvement of MEA as well as of metal ionsf in free radical formation in proteins and bacteria has been observed. It was also found that cysteine and glutathione could accept electrons from irradiated proteins, whereas cystine and non-sulfur compounds did not Presence of metal ions, particularly cupric, had a protective effect for ribo-nuclease, presumably by intercepting electrons and preventing radical formation on the enzymer A protective effect of mucopolysaccharide polyanions and cysteine for trypsin and RHA, however, was not considered to be due to transfer of radiation energy to the protectors " Furthermore, substances known to react with H atoms or the aqueous electron did not protect hydrated E. coll cells from X-rays ... 

Preston BD, Miller JA, Miller EC. 1984. Reactions of 2,2, 5,5 -tetrachlorobiphenyl-3,4-oxide with methionine, cysteine and glutathione in relation to the formation of methylthio-metabolites of 2,2, 5,5 -tetrachlorobiphenyl in the rat and mouse. Chem-Biol Ineract 50 289-312. 

Possible metabolites previously suggested include gold complexes of cysteine and glutathione ( ). We have examined solid samples of each of these and find them to fit satisfactorily to a model in which gold is coordinated to two bridging sulfur atoms with bond lengths identical to those found in the chronic sodium gold(I)thiomalate aurosomes. 

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