High activities of NADP+-dependent isocitrate dehydrogenase and malic enzyme in rabbit lens epithelial cells.
Measurements were made of the activities of the NADP+-dependent isocitrate dehydrogenase, malic enzyme and glucose-6-phosphate dehydrogenase in cytosolic supernatants of whole lens and capsule-epithelium. The activities of all three NADP+-dependent enzymes were concentrated in the capsule-epithelium relative to the activities measured in the whole lens. These results show for the first time that the rabbit lens epithelial cells contain substantial activities of the NADP+-dependent isocitrate dehydrogenase and malic enzyme. It is proposed that these enzymes together with glucose-6-phosphate dehydrogenase are involved in the regulation of the intracellular level of glutathione during oxidative stress by providing the NADPH necessary for the activity of glutathione reductase.
Winkler
B S
BS
Eye Research Institute of Oakland University, Rochester, MI 48309.
Solomon
F
F
D000818:Animals; D004847:Epithelial Cells; D004848:Epithelium / Q000201:enzymology; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D007521:Isocitrate Dehydrogenase / Q000378:metabolism*; D007908:Lens, Crystalline / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000378:metabolism*; D010101:Oxygen Consumption; D011817:Rabbits
D008291:Malate Dehydrogenase; D007521:Isocitrate Dehydrogenase; C039355:isocitrate dehydrogenase (NADP+); D005954:Glucosephosphate Dehydrogenase; D005978:Glutathione