Inactivation of anaerobic glycolysis in fractions of rat-brain homogenates

Abstract

A study is reported of the anaerobic conversion of fructose 1,6-diphosphate into lactate by fractions of rat-brain homogenate. A partial inactivation occurs when the fractions are assayed in a medium lacking sulphydryl compounds. Glutathione preserved the activity; cysteine was ineffective but the succinic acid ester of British anti-lewisite was nearly as effective as glutathione. Little or no stimulation of lactate production occurs when the mitochondrial and supernatant fractions are mixed and assayed in the glutathione-fortified medium. Published reports of a large stimulation were based on determination in an inadequate medium. Mitochondrial preparations from homogenates made with a high-speed smooth pestle homogenizer have about 21% of the summed fructose 1,6-diphosphate-glycolytic activity of mitochondria and supernatant. This proportion is decreased to 12% if a vigorous blade homogenizer is used and the fraction is more thoroughly washed. The distribution of aldolase in rat-brain fractions has been further studied and its predominant location (60%) in the supernatant fraction confirmed.