INTRACELLULAR DISTRIBUTION OF ENZYMES CATALYZING SUCCINATE PRODUCTION FROM GLUCOSE IN RANGIA MANTLE

1. 1. Succinate production in a number of invertebrates has been postulated to be the result of anaerobic glycolysis in the presence of inadequate levels of lactic dehydrogenase. The redox pair of phosphopyridine nucleotides is kept in the oxidized state by two reductive reactions: reduction of oxalacetate and reduction of fumarate. 2. 2. The production of oxalacetate from glucose has been demonstrated to occur anaerobically in Rangia mantle. All the reactions are catalyzed enzymes located in the cytoplasmic fraction of mantle. 3. 3. The reduction of oxalacetate and dehydration of malate are catalyzed by enzymes also located in the cytoplasmic fraction but the enzyme catalyzing the reduction of fumarate has been located within the mitochondria or particles corresponding to mammalian mitochondria. 4. 4. Fumarate is reduced by NADH in the mitochondria which in Rangia mantle, unlike mammalian mitochondria, appear to be permeable to NADH. © 1969.