[Radioisotopic assay of total L-homocysteine in plasma and urine: application to serial determinations].

The authors report here a simple radioenzymatic determination of total L-homocysteine in plasma and urine. L-homocysteine-containing disulfides were reduced with dithioerythritol. L-homocysteine was then condensed by S-adenosyl L-homocysteine hydrolase to 14C-adenosine to form S-14C adenosyl L-homocysteine that was separated from 14C-adenosine by paper descendant chromatography.