Chemoenzymatic and enzymatic cascade reactions enable the synthesis of complex stereocomplementary 1,3,4-trisubstituted tetrahydroisoquinolines (THIQs) with three chiral centers in a step-efficient and selective manner without intermediate purification. The cascade employs inexpensive substrates (3-hydroxybenzaldehyde and pyruvate), and involves a carboligation step, a subsequent transamination...

The refolding of rabbit muscle pyruvate kinase after denaturation by guanidine hydrochloride was studied. On dilution of the denaturing agent, enzyme activity is only partially regained. The extent of regain of activity is dependent on protein concentration, showing a marked decrease at higher concentrations. The failure to regain complete activity appears to be related to the formation of inac...

MATERIALS AND METHODS A nonaqueous fractionation method to obtain highly purifled mesophyll chloroplasts from lyophilized leaves ofZea mays L. is described. The levels of several metabolites including pyruvate were determined in the purified mesophyll chloroplast fractions which were prepared from leaves exposed to different light intensities. The role of pyruvate in the regulation of pyruvate,...

Biotin enzymes such as pyruvate carboxylase and acetyl-CoA carboxylase are involved with the most basic metabolism. Thus, it is very important to monitor the biotin nutritional status for maintaining good health. We examined urinary excretion and the intake of biotin in a Japanese sample population of 60 boys and 36 girls (10-12 y), 37 male and 135 female college students (18-27 y), and 35 fema...

Clostridial ferredoxin and pyruvate-ferredoxin oxidoreductase activity was investigated after in vitro or in vivo treatment with sodium nitrite. In vitro treatment of commercially available Clostridium pasteurianum ferredoxin with sodium nitrite inhibited ferredoxin activity. Inhibition of ferredoxin activity increased with increasing levels of sodium nitrite. Ferredoxin was isolated from norma...

The simultaneous release and uptake of lactate by the heart has been observed both in vivo and ex vivo; however, the pathways underlying these observations have not been satisfactorily explained. Consequently, the purpose of this study was to test the hypothesis that hearts release lactate from glycolysis while simultaneously taking up exogenous lactate. Therefore, we determined the effects of ...

A previous report dealt with the action of insulin on the fate of the 3 carbon atoms of lactate in the liver of the alloxan-diabetic rat (1). It was shown that insulin decreased the oxidation of the crand P-carbons of added lactate to COz and stimulated, in a pronounced manner, the incorporation of these 2 carbon atoms, as an intact unit, into fatty acids. In assessing the significance of these...

A simple automated method for the determination of lactic dehydrogenase (LDH) activity in serum by the forward lactate pyruvate reaction is presented. Enzyme activity is determined by measuringthe fluorescence of DPNH formed after a fixed incubation time. Detailed studies of various parameters of the reaction, reproducibility, and recovery data, and a comparisonwith two manual methods for LDII ...

Introduction: A stimulated-echo sequence with high sensitivity to diffusion and flow is shown here to provide a valuable contrast mechanism for hyperpolarized C metabolic imaging (1-4). This mechanism can highlight stationary metabolites, while suppressing signal from flowing metabolites. This helps to distinguish whether C-pyruvate is converted to Clactate within the tissue or whether the C-la...

The discovery of carbon dioxide assimilation by heterotrophic bacteria (1) and animal tissues (2) aroused considerable interest in the mechanisms involved. Evidence from various sources suggested the Wood and Werkman reaction, i.e. the carboxylation of pyruvate to oxalacetate, as a major pathway (3). Evans, Vennesland, and Slotin (4) discovered that pigeon liver extracts fixed (‘02 in the prese...