Pyruvic acid biological reduction

Biological reduction of pyruvic acid catalyzed by the enzyme... 

This reaction is completely enantioselective. For example, reduction of pyruvic acid with NADH catalyzed by lactate dehydrogenase affords a single enantiomer of lactic acid with the S configuration. NADH reduces a variety of different carbonyl compounds in biological systems. The configuration of the product (/ or S) depends on the enzyme used to catalyze the process. 

The NAD -NADH coenzyme system is involved in a large number of biological oxidation-reductions. Another reaction similar to the ethanol-acetaldehyde conversion is the oxidation of lactic acid to pyruvic acid by NAD and the enzyme lactic acid dehydrogenase ... 

Lactams, 803 Lactase, 993 Lactic acid, 737, 1015 biological oxidation of, 602 (5 ) enantiomer by enzymic reduction of pyruvic acid, 681-682,1015 Lactones, 758-759, 788 formation of... 

Nicotinamide adenine dinucleotide (NADH) supplies a hydride ion for reductions of carbonyl groups in biological systems. NADH is converted to NAD" in the process. An example is the reduction of pyruvic acid to lactic acid, which occurs during the metabolism of glucose ... 

Biological reduction of pyruvic acid, catalyzed by the enzyme lactate dehydrogenase, gives (+)-lactic acid, represented by the Fischer projection shown. What is the configuration of (+)-lactic acid according to the Cahn-Ingold-Prelog R-S notational system ... 

Until 1993, all terpenes were considered to be derived from the classical acetate/mevalonate pathway involving the condensation of three units of acetyl CoA to 3-hydroxy-3-methylglutaryl CoA, reduction of this intermediate to mevalonic acid and the conversion of the latter to the essential, biological isoprenoid unit, isopentenyl diphosphate (IPP) [17,18,15]. Recently, a totally different IPP biosynthesis was found to operate in certain eubacteria, green algae and higher plants. In this new pathway glyceradehyde-3-phosphate (GAP) and pyruvate are precursurs of isopentenyl diphosphate, but not acetyl-CoA and mevalonate [19,20]. So, an isoprene unit is derived from isopentenyl diphosphate, and can be formed via two alternative pathways, the mevalonate pathway (in eukaryotes) and the deoxyxylulose pathway in prokaryotes and plant plastids [16,19]. 

For the determination of keto-acids, e.g. pyruvic, a-ketoglutaric and oxalacetic acids in mixtures and in biological materials, a method has been proposed employing paper electrophoretic separations of the 2,4-dinitrophenylhydrazones of these acids.< ) After elution, the polarographic wave corresponding to the reduction of the nitro-groups (in the 2,4-dinitrophenylhydrazone formed) was followed in 0-1 N HCl and the first wave at —0T4 V measured. 

It has been known for a long time that nature has employed a reductive amination protocol in biological systems. Transferase enzymes use hydrogen bonding to activate pyruvate-derived ketimines selectively toward hydride delivery from NADH, thereby ensuring the enantiocontroUed formation of naturally occurring amino acids. 

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