Oxidation cysteine

K Barlos, D Gatos, S Kutsogianni, G Papaphotiou, C Poulus, T Tsegenidis. Solid phase synthesis of partially protected and free peptides containing disulphide bonds by simultaneous cysteine oxidation-release from 2-chlorotrityl resin. Int J Pept Prot Res 38, 562, 1991. 

Dillard CJ, Tappel AL. 1986. Mercury, silver, and gold inhibition of selenium-accelerated cysteine oxidation. J Inorg Biochem 28 13-20. 

Figure 134 Cysteine oxidation and disulfide bond formation (See also Fig. 67).

Kundo, N.N., Keier, N. P. Catalytic Activity of Organic Copper Complexes in Cysteine Oxidation. Kinetika Katal. 8, 796 (1967). C. A. 68, 30008e (1968). 

Poole LB, Nelson KJ (2008) Discovering mechanisms of signaling-mediated cysteine oxidation. Curr Opin Chem Biol 12 18-24... 

The method of sulfide determination is based on what is commonly known as Lauth s reaction, and is adapted from the original method of Fisher (42). It involves a specific use of S in the synthesis of methylene blue from N,N-dimethylphenylenediamine (Fogo and Popowsky (43)). Cysteine, oxidized and reduced glutathione, insulin, and bovine serum albumin do not react in this test, thus indicating its specificity for sulfide (Lovenberg, Buchanan, and Rabinowitz (63)). 

Ito S, Fujita K (1981) Iron- and peroxide-dependent conjugation of dopamine with cysteine oxidative routes to the novel brain metabolite 5-S-cysteinyldopamine. Biochim Biophys Acta 672 151-157... 

Such chemical changes may lead to compounds that are not hydrolyzable by intestinal enzymes or to modifications of the peptide side chains that render certain amino acids unavailable. Mild heat treatments in the presence of water can significantly improve the protein s nutritional value in some cases. Sulfur-containing amino acids may become more available and certain antinutritional factors such as the trypsin inhibitors of soybeans may be deactivated. Excessive heat in the absence of water can be detrimental to protein quality for example, in fish proteins, tryptophan, arginine, methionine, and lysine may be damaged. A number of chemical reactions may take place during heat treatment including decomposition, dehydration of serine and threonine, loss of sulfur from cysteine, oxidation of cysteine and methio-... 

Protein contaminants can occur as natural isoforms or can arise during purification. Adventitious proteolysis and cysteine oxidation are probably the most common sources of microheterogeneity that occur during isolation (Lorber et al, 1987). This has frequently motivated the inclusion of protease inhibitors and/or reducing agents in crystallization solutions, as well as during purification. In many cases modifications that produce molecular heterogeneity are reflected in enzyme activity. For... 

The surface coverage (T) and heterogeneous electron transfer rate constant (ks) of adsorbed redox couple were about 9.5 10 9 mol cm 2 and 3.18 ( 0.20) s 1, respectively, indicating the high loading ability of ZnOx nanoparticles toward guanine oxidation product and great facilitation of the electron transfer between redox couple and ZnOx nanoparticles. The modified electrode exhibited excellent electrocatalytic activity toward L-cysteine oxidation. The kcat for L-cysteine oxidation was found to be 4.20( 0.20)x 103 M V1. The catalytic oxidation current allows the amperometric detection of L-cysteine at potential of 0.5 V with detection limit of 50 nM, linear response up to 20 p, M and sensitivity of 215.4 nA.p A" em"2 This results indicate ZnO nanoparticles modified electrodes are suitable microenvironment for observation and stabilization of unusual and unstable redox couples. 

Crowe A, James MJ, Lee VM, Smith AB 3rd, Trojanowski JQ, Ballatore C et al (2013) Aminothienopyridazines and methylene blue affect Tau fibrillization via cysteine oxidation. J Biol Chem 288 11024-11037... 

Vina J,Saez GT, Wiggins D, Roberts AF, Hems R, Krebs HA (1983) The effect of cysteine oxidation on isolated hepatocytes. Biochem J 212(1) 39—44... 

Glutathionylation may inhibit proteins, yet there is an important difference from inactivation by oxidation of cysteine residues by ROS, forming sulfinic or sulfonic acids. Both cysteine oxidation states are generally regarded as not reducible under cellular conditions although the cellular reduction and reactivation of a peroxiredoxin cysteine sulfinic acid has recently been described ... 

Miki H, Funato Y (2012) Regulation of intracellular signalling through cysteine oxidation by reactive oxygen species. J Biochem 151 255-261... 

CYSTEINE OXIDATION The sulfhydryl group of cysteine is highly reactive. 

Amino acids undergo several chemical reactions. Two reactions are especially important peptide bond formation and cysteine oxidation. 

Structure governing the ionization or pK of cysteine residue will also influence the cysteine oxidation rate [49, 59], As demonstrated using seminal ribonucleases segment 29-34 [60] and a-lactalbumin [61], introduction of an electronegative environment into the structures raises the pK of the thiol groups and reduces the cysteine oxidation rate. In contrast, cysteine residue in papain, which displays a lower pKa due to the presence of a nearby ionizable histidine group, is chemically more reactive than expected [59],... 

The electron transfer from the iron complex to oxygen is a limiting step. The kinetics of cysteine oxidation are described by the equation W=k [RSH] [catalyst] [02] [0H ], the activation energy is 36.8kJ/mole. 

Reverse phase HPLC (RP-HPLC) is the final cleanup step and leaves the protein in a volatile solvent suitable for lyophiHzation. Chemokines are functional when refolded and refolding involves cysteine oxidation and correct pairing in disulfide bonds. First, RP-HPLC is used to check for cysteine oxidation and disulfide bond formation. Then RP-HPLC is used to cleanup... 

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