A sensitive, continuous spectrophotometric method for assaying alpha-glycerophosphate dehydrogenase: activation by menadione.

By use of a more sensitive method than standard assays, it is demonstrated that alpha-glycerophosphate dehydrogenase activity can be monitored continuously in rat liver mitochondria; maximum activity was obtained by sonication in the presence of Triton X-100. Vitamin K3 (menadione) seems to enhance the activity of the enzyme. The assay in the presence of menadione is linear over a much greater mitochondrial concentration (up to 250 micrograms of protein in the reaction mixture).