Oxygen, biochemical reactivity

Hagen T (2012) Oxygen versus reactive oxygen in the regulation of HIF-lalpha the balance tips. Biochem Res Int 2012 436981. doi 10.1155/2012/436981... 

Ascorbic acid is a reasonably strong reducing agent. The biochemical and physiological functions of ascorbic acid most likely derive from its reducing properties—it functions as an electron carrier. Loss of one electron due to interactions with oxygen or metal ions leads to semidehydro-L-ascorbate, a reactive free radical (Figure 18.30) that can be reduced back to L-ascorbic acid by various enzymes in animals and plants. A characteristic reaction of ascorbic acid is its oxidation to dehydro-L-aseorbie add. Ascorbic acid and dehydroascor-bic acid form an effective redox system. 

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Patel, A. K., Hallett, M. B., Campbell, A. K. (1987). Threshold responses in production of reactive oxygen metabolites in individual neutrophils detected by flow cytometry and microfluorimetry. Biochem. J. 248, 173-80. 

Poulsen AK, Scharff-Poulsen AM, Olsen LF (2007) Horseradish peroxidase embedded in polyacrylamide nanoparticles enables optical detection of reactive oxygen species. Anal Biochem 366 29-36... 

Thioesters are more reactive towards nucleophilic substitution than oxygen esters, and are widely employed in natural biochemical processes because of this property. Coenzyme A is a structurally complex thiol, and functions in the transfer of acetyl groups via its thioester acetyl coenzyme A (acetyl-CoA CH3CO-SC0A). 

Boldyrev, A., Bulygina, E., Leinsoo, T., Petrshanko, I., Tsebone, S., and Abe, H. (2004a). Protection of neuronal cells against reactive oxygen species by carnosine and related compounds. Comp. Biochem. Physiol. B Biochem. Mol. Biol. 137, 81-88. 

CN021 Joe, B. and B. R. Lokesh. Role of capsaicin, curcumin and dietary N-3 fatty acids in lowering the generation of reactive oxygen species in rat peritoneal macrophages. Biochem Biophys Acta 1994 1224(2) 255-263. 

Wiseman H, Halliwell B. Damage to DNA by reactive oxygen and nitrogen species role in inflammatory disease and progression to cancer. Biochem. J. 313, 17-29, 1996. 

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