Free-radical damage to lipids, amino acids, carbohydrates and nucleic acids determined by thiobarbituric acid reactivity.

1. The thiobarbituric acid (TBA) reaction, widely applied to the detection of autoxidation in polyunsaturated fatty acids, can be used to measure free-radical damage to amino acids, carbohydrates and nucleic acids. 2. In all of these systems malondialdehyde (MDA) is predominately formed from intermediate precursor molecules which break down during the acid-heating stage of the TBA test. 3. The acid reagent used to bring about these decompositions appears to be critical.