We have observed that rodent cell lines (mouse, hamster) contain approximately 10 times the levels of dihydrofolate reductase as human cell lines, yet the sensitivity to methotrexate (ED(50)), the folate antagonist that targets this enzyme, is similar. Our previous studies showed that dihydrofolate reductase protein levels increased after methotrexate exposure, and we proposed that this increas...

Ferredoxin reductase (Fd-reductase) supplies electrons to mitochondrial steroid hydroxylase cytochrome P450 enzymes via a [2Fe-2S] ferredoxin. Chemical labeling studies with bovine Fd-reductase have implicated Lys-243 as important in binding to bovine ferredoxin (Hamamoto, I., Kazutaka, K., Tanaka, S., and Ichikawa, Y. (1988) Biochim. Biophys. Acta 953, 207-213). We have used site-directed muta...

The endoplasmic reticulum enzyme 3-hydroxy-3-methylglutaryl-CoA reductase produces mevalonate, which is converted to sterols and to other products, including geranylgeraniol groups attached to proteins. The enzyme is known to be ubiquitinated and rapidly degraded when sterols and nonsterol end products of mevalonate metabolism accumulate in cells. Here, we use RNA interference to show that ster...

chlD mutants of Escherichia coli lack active nitrate reductase but form normal levels of this enzyme when the medium is supplemented with 10-3 M molybdate. When chlD mutants were grown in unsupplemented medium and then incubated with molybdate in the presence of chloramphenicol, they formed about 5% the normal level of nitrate reductase. Some chlD mutants or the wild type grown in medium supple...

Malaria caused by Plasmodium falciparum , remains one of the most fatal parasitic diseases that has affected nearly a third world’s population. The major impediment to treatment malaria is emergence resistance P. parasite current anti-malaria therapeutics such as Artemisinin (ART)-based combination therapy (ACT). This resulted in countless efforts develop novel will counter this with aim contro...

Germinating cotton (Gossypium hirsutum L. cv. Deltapine 16) cotyledons developed two peaks of in vitro nitrate reductase activity; the first was stable in vitro and appeared 24 hours after imbibition; and the second, which was extremely labile in vitro, began to develop after the seedlings had emerged and developed chlorophyll. Nitrite reductase activity peaked only after the seedlings had emer...

MYC is a potential target for many cancers but is not amenable to existing pharmacologic approaches.Inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase) by statins has shownpotential efficacy against a number of cancers. Here, we show that inhibition of HMG-CoA reductase byatorvastatin (AT) blocks both MYC phosphorylation and activation, suppressing ...

Nitrate reductase-deficient barley (Hordeum vulgare L.) mutants were assayed for the presence of a functional molybdenum cofactor determined from the activity of the molybdoenzyme, xanthine dehydrogenase, and for nitrate reductase-associated activities. Rocket immunoelectrophoresis was used to detect nitrate reductase cross-reacting material in the mutants. The cross-reacting material levels of...

The accumulation of free lysine in tobacco seed triggers the stimulation of lysine-ketoglutarate reductase, an enzyme that acts in lysine catabolism. The mechanism of lysine-ketoglutarate reductase stimulation was studied in two different systems: (1) developing seeds of wild-type plants in which the low basal lysine-ketoglutarate reductase activity can be stimulated by the exogenous addition o...

A search of the disulfide reductase activities expressed in the adult stage of the free-living platyhelminth Dugesia dorotocephala was carried out. Using GSSG or DTNB as substrates, it was possible to obtain a purified fraction containing both GSSG and DTNB reductase activities. Through the purification procedure, both disulfide reductase activities were obtained in the same chromatographic pea...