Histochemical and Homogenization Studies of Mitochondrial α-Glycerophosphate Dehydrogenase in the Nervous System

Abstract

AN insoluble brain enzyme capable of oxidizing α-glyeerophosphate¹ has been shown to be part of a purely mitochondrial system which resembles suc-cinate dehydrogenase in that pyridine nucleotides do not participate in electron transfer². Histochemical localization of this activity in mammalian nervous tissue was made difficult by the fact that tetrazolium salts are ineffective electron-acceptors in preparations which oxidize α-glycerophosphate. Maximal reaction-rates, however, were obtained by using 2-methyl-1,4-naphthoquinone (menadione, K₃) as intermediate acceptor. Histochemically, this effect was first demonstrated by Wattenberg in liver slices³. We found that menadione could be substituted by the sodium bisulphite derivative, but the diphosphoric acid ester (‘Synkavite’), vitamin K₁, and 1,4-benzo-quinone were ineffective.