3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity in microsomes isolated from cultured lymphoid (IM-9) cells or freshly isolated human leukocytes was markedly decreased by either ascorbic acid or its oxidized derivative, dehydroascorbate. Inhibition of IM-9 leukocyte HMG-CoA reductase activity was log linear between 0.01 and 10 mM ascorbic acid (25 and 81% inhibition, respectiv...

Abbreviations: ROS: Reactive oxygen species; H2O2: Hydrogen peroxide; CAT: Catalase; POD: peroxidase; APX: Ascorbic Acid Peroxidase; GR: Glutathione Reductase; AsA-GSH: Ascorbate-Glutathione; ASC: Reduced form of Ascorbate; DHA: Dehydroascorbate; MDHAR: Monodehydroascorbate Reductase; DHAR: Dehydroascorbate reductase; GSH: Reduced Glutathione; GSSG: Oxidized Glutathione; PDA: Potato Dextrose Ag...

Glutathione dehydrogenase (EC 1.8.5.1) was partially purified from pea shoots. The pH optimum was 7.6. The K(m) values for GSH and dehydroascorbate were 4.4 and 0.44 millimolar, respectively. The enzyme was inhibited by iodoacetate and CuSO(4) but not significantly by ZnCl(2) or NaN(3). Part of the total enzyme activity was associated with isolated chloroplasts.Illuminated ruptured chloroplasts...

The metabolism of glucose through the hexose monophosphate (HMP) shunt has been studied in rat lens in vitro, in the absence and presence of ascorbic and dehydroascorbic acids. Both forms of the vitamin stimulated the utilization of glucose through the HMP shunt, the stimulatory effect of dehydroascorbate being substantially greater than that of ascorbate. The stimulatory effect of ascorbate, a...