PURPOSE This study was undertaken to investigate whether thioltransferase (TTase) exhibits dehydroascorbate (DHA) reductase activity in human lens epithelial cells. METHODS TTase was investigated for DHA reductase activity in vitro by the method of glutathione reductase-coupled spectrophotometric assay. DHA reductase activities of human lens epithelial (HLE-B3) cell lysate and TTase-depleted ...

Administration of dexamethasone to hypophysectomized rats treated with thyroid hormones blocked the increase in hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase mRNA and enzyme activity which occurred in response to thyroid hormone treatment. The rate of transcription of the rat liver HMG-CoA reductase gene measured by "run-on" assays in isolated nuclei was not diminished by de...

The method for two-dimensional hybridization mapping of nucleosomes (Levinger, L., Barsoum, J., and Varshavsky, A. (1981) J. Mol. Biol. 146, 287-304) was used to analyze chromatin structure of the gene for dihydrofolate reductase (DHF reductase; 5,6,7,8-tetrahydrofolate:NADP+ oxidoreductase (EC 1.5.1.3)) in L5178Y-R mouse cells. The DHF reductase gene in these cells is amplified about 350-fold ...

The effect of different sources of nitrate salts (ammonium nitrate, sodium nitrate and potassium nitrate) on nitrate reductase (NR) activity and nitrate reductase expression in the leaves of Foeniculum vulgare seedlings grown in pots containing perlite. Two week old seedlings were treated with 30, 60 and 120 mM aqueous solution of ammonium nitrate, sodium nitrate or potassium nitrate. After 21 ...

Nitrate reductase from mutant 305 o f Chlamydomonas reinhardii has been purified about 90-fold and biochemically characterized. The enzyme can use reduced flavins and viologens as electron donors to reduce nitrate but, unlike the nitrate reductase com plex from its parental wild strain, lacks NAD(P)H-nitrate reductase and NAD(P)H-cytochrom e c reductase activities, does not bind to Blue-Agarose...

Photooxidative destruction of chloroplasts by exposure of norflurazon-treated cucumber (Cucumis sativus L.) seedlings to white light leads to reduced levels of the nuclear-encoded, peroxisomal enzyme hydroxypyruvate reductase. The partial reduction in hydroxypyruvate reductase activity under photooxidative conditions is accompanied by reductions in levels of hydroxypyruvate reductase protein an...

Methods were developed for the assay of hydroxymethylglutaryl-CoA reductase (NADPH) activity in microsomes from rat leukocytes. The activity in freshly isolated leukocytes is low compared to rat liver but can be assayed reliably. The patterns of response of leukocyte reductase in the assay to variation in substrate concentration, protein concentration, and time mimic those of rat liver reductas...

Greenhouse grown seedlings of corn (Zea mays L.) and foxtail (Setaria faberii Herrm.) were used as source material in determining the intracellular localization of nitrate reductase, nitrite reductase, and glutamic acid dehydrogenase, Nonaqueous and aqueous isolation techniques were used to establish that nitrite reductase is localized within the chloroplasts, but that nitrate reductase and glu...

Capillary basement membrane thickening is typical of the diabetic retina, and aldose reductase appears to be involved since a diabetic-like thickening can be induced by galactose feeding and prevented with aldose reductase inhibitors. Because aldose reductase is present in the Mueller's cells, studies were undertaken to determine if thickening of the retinal inner limiting membrane, which is th...