Relative activities of NAD- and NADP- isocritric dehydrogenases in bean mitochondria modified by glycerol or NADP.
Mitochondria from cotyledons of Vigna sesquipedalis (L.) Fruwirth (starchy seed) showed no NAD-isocitric dehydrogenase (NAD-IDH) activity by the methods which have been known to be useful for the detection of NAD-IDH in mitochondria of plants including castor bean and alaska pea. When the Vigna cotyledon mitochondria were treated with glycerol, NAD-IDH activity appeared and NADP-isocitric dehydrogenase (NADP-IDH) activity was inhibited. The inhibition of mitochondrial NADP-IDH by glycerol was overcome by the addition of excess NADP. On the other hand, NADP-IDH activity in the soluble fraction of cell components was only slightly inhibited by glycerol and no NAD-IDH activity was elicited. It was postulated that NADP-IDH in mitochondria is converted to NAD-IDH by glycerol and back to NADP-IDH with NADP by the alteration in the spatial configuration of the enzyme. However, there could be 2 proteins as the other possibility. The NADP-IDH in the soluble fraction which is not subject to such alteration is different from the mitochondrial NADP-IDH.
D005990:Glycerol / Q000494:pharmacology*; D008928:Mitochondria / Q000201:enzymology*; D009249:NADP / Q000494:pharmacology*; D010088:Oxidoreductases / Q000037:antagonists & inhibitors*; D010944:Plants / Q000201:enzymology; D012639:Seeds / Q000201:enzymology*
D009249:NADP; D010088:Oxidoreductases; D005990:Glycerol