Abstract: | Placental aldose reductase (EC 1.1.1.21) was incubated with glucose in the presence of 4A-2H] NADPH prepared in the oxidation of 2-2H] isocitrate by isocitrate dehydrogenase (EC 1.1.1.42) or 4B-2H] NADPH prepared in the oxidation of 1-2H] glucose-6-phosphate dehydrogenase (EC 1.1.1.49). The sorbitol formed from 4A-2H] NADPH contained deuterium and from 4B-2H] NADPH it did not. Therefore, aldose reductase in an A-type enzyme. |