HLTH340 Study Guide - Retinopathy Of Prematurity, Bronchopulmonary Dysplasia, Oxygen Toxicity
20 Dec 2013
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Topic 15: toxicodynamic mechanisms - free-radical toxicity part ii. Expound where necessary: exogenous radicals environmental oxidants (o3, no2) Mitochondria: et chain for oxidative phosphorylation (atp production) Lysosomes: oxidative burst in phagocytosis ( killing action") cell membrane: synthesis of inflammatory mediators (e. g. prostaglandin synthetases) Production of superoxide radical by 1-electron rxn at complex ii in the mitochondrial et chain. So let"s look into an example of how an accidental one-electron transfer can happen. Cytochrome c is the shuttle from 3 to 4. Coenzyme-q is the shuttle between 1 and 3: the point is that co-q is unfortunately accident prone/sloppy. Sometimes (1% or less), it will accidentally create a one-electron transfer (yikes!) - this gives the opportunity to have a superoxide, which you recall is o2: and thus we say that this is the leaky part of electron transfer. Pro-oxidants (i. e. nitrite), and what they can cause with oxygen and heme.
