Microplate-based kinetic method for assay of mitochondrial NADH-- and succinate--cytochrome c reductase activities.

This article describes a microplate-based kinetic assay for mitochondrial NADH-- and succinate--cytochrome c reductase activities in rat brain mitochondria. The assay reported here is based on the conventional spectrophotometric method and involves substrate-driven reduction of exogenous cytochrome c. Conditions regarding linearity with respect to time and protein concentration have been standardized. Furthermore, the methods were tested for inhibition of respective activities by specific inhibitors. The microplate format described here can be employed for rapid and simultaneous measurements of mitochondrial NADH-- and succinate--cytochrome c reductase activities in a large number of samples.