Oxygen metabolism, transition metal

Halliwell B, Gutteridge JMC (1984) Oxygen toxicity, oxygen radicals, transition metals and disease. Biochem J 219 1-14 Hamer DH (1986) Metallothionein. Annu Rev Biochem 55 913-951 Hamet P (1992) Abnormal hsp70 gene expression its potential key role in metabolic defects in hypertension. Clin Exp Pharmacol Physiol [Suppl] 20 53-59 Hansen DK, Anson JF, Hinson WG, Pipkin JL Jr (1988) Phenytoin-induced stress protein synthesis in mouse embryonic tissue. Proc Soc Exp Biol Med 189 136-140... 

It is well over 40 years since Pfeiffer discovered that certain reactions of a-amino acid esters, in particular, ester exchange, racemization and oxygenation, are effected very readily when their Schiff bases with salicylaldehyde are complexed to a transition metal ion (most notably Cu11). The Schiff bases result from a condensation reaction between a reactive carbonyl group and the amino group of the amino acids. Snell and his co-workers43 were also one of the first to point out that similar reactions also occurred if pyridoxal was used instead of salicylaldehyde, and that there is a close analogy with pyridoxal phosphate-promoted enzymic reactions of a-amino acid metabolism. Since then much work has been due on these and other similar systems and their reactivities. 

In summary, the ROS that initiate lipid peroxidation include oxygen itself, superoxide, hydrogen peroxide, transition metal ions, and the hydroxyl radical. These ROS are normally produced during metabolism and in the absence of adequate defense mechanisms ROS can attack DNA, proteins, and lipids in the body. However, ROS are not always harmful. For example, they are involved in the destruction of pathogens by phagocytes. 

The transition metals iron and copper are essential cofactors of several enzymes which are involved in oxygen metabolism. Approximately two-... 

Carbon monoxide is neutral and only sparingly soluble in water. It forms metal carbonyls with transition metals. Its toxicity derives from the fact that hemoglobin (in the blood) has a far stronger affinity for carbon monoxide than for oxygen, which is essential for cell metabolism. 

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