A hypothesis for a role for unsaturated fatty acids in electron transport and its potential application to understanding the mitochondrial respiratory chain.

Unsaturated fatty acids are required for mitochondrial oxidative phosphorylation and electron transport, though their role has not been determined. We have considered the possibility that unsaturated fatty acids might facilitate electron transfer from non-heme iron to heme iron. Unsaturated fatty acids markedly enhanced the reduction of ferric cytochrome c by ferrous iron. Neither stearic acid nor methyl arachidonic acid were effective suggesting that both a double bond and the carboxylic acid group were essential. Thus unsaturated fatty acids can directly facilitate electron transfer from non-heme iron to heme iron. We hypothesize that unsaturated fatty acids may play a similar critical role in mitochondrial oxidative phosphorylation and other biological processes where rapid electron transfer occurs.