Determination of thymine ring saturation products of the 5,6-dihydroxydihydrothymine type by the alkali degradation assay.

Thymine ring saturation products of the 5,6-dihydroxydihydrothymine type in cellular DNA were determined by measuring the acetol fragment released using either alkali followed by acid and heat treatments or alkali treatment alone. The alkali degradation assay was simpler and more sensitive, yielding an increase of approximately 40% in detection efficiency of acetol compared to the previously used alkali-acid degradation assay.