The crystal structures of three forms of Escherichia coli thioredoxin reductase have been refined: the oxidized form of the wild-type enzyme at 2.1 A resolution, a variant containing a cysteine to serine mutation at the active site (Cys138Ser) at 2.0 A resolution, and a complex of this variant with nicotinamide adenine dinucleotide phosphate (NADP+) at 2.3 A resolution. The enzyme mechanism inv...

Mercuric chloride was introduced per Os in albino rats (Rattus norvegicus) as the LD50 (9.26 mg/kg b.w.). The assessment of mercuric toxicity done both after acute (0.926 b.w.) and sub-acute (0.033 treatment, while Panax ginseng also (10 separately. treatment significantly increases mercury retention liver blood serum along with increase weight, alone caused significant decrease weight blood. I...

The folate antagonists, in particular amethoptenin (methotrexate), continue to be useful drugs for the treatment of certain neoplastic diseases in man. The effectiveness of amethoptenin in preventing DNA synthesis and cellular replication appears to be a consequence of inhibition of the enzyme dihydrofolate reductase. This premise is sup ported by in vivo studies which show that in patients tre...

The aim of this study was to define mechanisms involved in the luminal uptake of inorganic mercury in the kidney using isolated perfused straight (S2) segments of the proximal tubule. When mercuric conjugates of glutathione (GSH), cysteinylglycine. or cysteine (containing 203Hg2+) were perfused through the lumen, the rates of luminal disappearance flux (JD) of inorganic mercury were approximate...

This two-site immunoassay measures erythrocyte aldose reductase by using monoclonal and polyclonal antibodies to recombinant human enzyme. Total incubation time is 2.5 h, and the limit of detection is < 0.05 microgram/L. Analytical recovery tested with blood samples from healthy and diabetic individuals was 101-106%. Average CVs within and between assays were 3.7% and 4.8%, respectively. The en...

The first enzyme of the lysine degradation pathway in maize (Zea mays L.), lysine-ketoglutarate reductase, condenses lysine and [alpha]-ketoglutarate into saccharopine using NADPH as a cofactor, whereas the second, saccharopine dehydrogenase, converts saccharopine to [alpha]-aminoadipic-[delta]-semialdehyde and glutamic acid using NAD+ or NADP+ as a cofactor. The reductase and dehydrogenase act...

Immunoprecipitation of native rat liver microsomal 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, phosphorylated by [gamma-32P]ATP in the presence of reductase kinase, revealed a major 97-kDa 32P band which disappeared upon competition with pure unlabeled 53-kDa HMG-CoA reductase. A linear correlation between the expressed/total HMG-CoA reductase activity ratio (E/T) and the fractio...

Wetland grasses and grass-like monocots are very important natural remediators of pollutants. Their genetic improvement is an important task because introduction of key transgenes can dramatically improve their remediation potential. Tissue culture is prerequisite for genetic manipulation, and methods are reported here for in vitro culture and micropropagation of a number of wetland plants of v...

The activity of a ribonucleoside reductase was estimated during the life cycle of Acetabularia. During the early generative phase the enzyme activity was dramatically increased. Regulation of the ribonucleoside reductase was observed even in the absence of the nucleus. The increase in activity was inhibited by chloramphenicol but not by cycloheximide. These results indicate that the enzyme is t...

The partial purification of the enzyme, aromatic aldehydeketone reductase (aromatic A-K reductase), from rabbit kidney cortex is described. Aromatic A-K reductase utilizes TPNH but not DPNH as a cosubstrate. Substituted benzaldehydes and acetophenones are readily reduced to carbinols. Aromatic A-K reductase does not, however, catalyze the reverse reaction, the dehydrogenation of carbinols under...