Radical reactions proteins

Radical reactions of protein. Radical reactions of proteins promoted by lipid hydroperoxides fall into three general categories (a) protein-protein or lipid-protein crosslinking, (b) protein scission, and (c) protein oxidation. 

Such free radicals may be stabilized by binding to proteins. Redox reactions may also occur between ionic species, for example the oxidation of reduced cytochrome c by hexacyanoferrate (ferricyanide) ions. 

Adams, G.E. and Redpath, J.L. (1974). Selective free-radical reactions with proteins and enzymes pulse radiolysis and inactivation studies on papain. Int. J. Badiat. Biol. 25, 129-136. 

NADH, which enters the Krebs cycle. However, during cerebral ischaemia, metabolism becomes anaerobic, which results in a precipitous decrease in tissue pH to below 6.2 (Smith etal., 1986 Vonhanweh etal., 1986). Tissue acidosis can now promote iron-catalysed free-radical reactions via the decompartmentalization of protein-bound iron (Rehncrona etal., 1989). Superoxide anion radical also has the ability to increase the low molecular weight iron pool by releasing iron from ferritin reductively (Thomas etal., 1985). Low molecular weight iron species have been detected in the brain in response to cardiac arrest. The increase in iron coincided with an increase in malondialdehyde (MDA) and conjugated dienes during the recirculation period (Krause et al., 1985 Nayini et al., 1985). 

Elastin-mimetic protein polymers have been fabricated into elastic networks primarily via y-radiation-induced, radical crosslinking of the material in the coacervate state [10]. Although effective, this method cannot produce polymers gels of defined molecular architecture, i.e., specific crosslink position and density, due to the lack of chemoselectivity in radical reactions. In addition, the ionizing radiation employed in this technique can cause material damage, and the reproducibility of specimen preparations may vary between different batches of material. In contrast, the e-amino groups of the lysine residues in polymers based on Lys-25 can be chemically crosslinked under controllable conditions into synthetic protein networks (vide infra). Elastic networks based on Lys-25 should contain crosslinks at well-defined position and density, determined by the sequence of the repeat, in the limit of complete substitution of the amino groups. 

Hawkins, C.L. Davies, M.J. Generation and propagation of radical reactions on proteins. Biochim. 

The self-peroxidation reactions of Cu,Zn-SOD provide a particularly novel mechanism for the formation of protein radicals. Hydrogen peroxide is generated during the reaction cycle of the enzyme ... 

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