The effect of oxidized fatty acids on the activity of certain oxidative enzymes

1. 1. Incubation of washed tissue suspensions or mitochondria with ascorbic acid inactivates a number of enzymes including the succinoxidase, cytochrome oxidase, and choline oxidase. It has no effect on liver alkaline phosphatase or brain cholinesterase. 2. 2. The extent of inactivation parallels the amount of oxidized fatty acid formed as measured by the thiobarbituric acid (TBA) reagent. Quercetin which inhibits oxidation prevents the inactivation. 3. 3. Methyl linolenate previously exposed to ultraviolet light also inhibits the oxidative enzymes. In the same concentrations, unexposed linolenate has little or no effect. 4. 4. The inhibition by oxidized linolenate occurs slowly, which indicates a slow reaction with some enzyme component.