Pyruvate/pyruvic acid

METHYL PYRUVATE (Pyruvic acid, methyl ester)... 

D. Lipidland. As the liver is not turning out glucose, alternate sources of energy must be increased. Triglycerides break down in fet cells to release fatty acids, with elevation of serum lipids. There may be fetty deposits (xanthomas) in various parts of the body. The excess pyruvate (pyruvic acid) and lactate (lactic acid) result in a serum acidosis. 

Pyruvic acid ethyl ester. See Ethyl pyruvate Pyruvic acid, sodium salt. See Sodium pyruvate Pyruvic aldehyde. See Pyruvaldehyde Pyruvophenone. See 1-Phenyl-1,2-propanedione... 

NADH/NAD = nicotinamide adenine dinucleotide, pyruvate = pyruvic acid, formazan = tetrazolium dye, LDH = lactate dehydrogenase. 

Pyruvic acid is important as an intermediate in sugar metabolism. This acid is formed as the final product of the glycolytic pathway from 3-phosphoglycerate via phosphoenolpyruvate. Pyruvic acid is also formed through the oxidative pentose phosphate cycle. The degradation of glucose in the cycle yields the C3 product glyceraldehyde 3-phosphate, which can be oxidized to pyruvate. Pyruvic acid is the principal precursor for the biosynthesis of amino acids such as alanine, as well as leucine and valine. 

Occurs in coal tar, in various plants and in faeces, being formed by the action of the intestinal bacteria on tryptophan. It can be prepared by the action of acid on the phenyl-hydrazone of pyruvic acid to give indole-2-carboxylate which can be decarboxylated to indole. 

For the mechanism of this reaction, see Robinson and Robinson,1918, H3i 639 1924, 145, 827.) The reaction is of wide application for example, the use of methyl-phenyl-hydrazine, CsH5(CHj)> -iN H, in the above reaction gives i-methyl-2-phenylindole, whereas pyruvic acid, CH CO COOH, when converted to its phenylhydrazone and then indolised, gives indole-2-carboxylic... 

The benzoic acid may be separated by steam distillation or by saturating the aqueous mixture of sodium salts with sulphur dioxide whilst maintaining the temperature below 40° the benzoic acid precipitates and can be separated by filtration or extraction with ether. Acidification of the filtrate with hydrochloric acid liberates the pyruvic acid. The pjTuvic acid may be oxidised < lth hydrogen peroxide to the arylacetic acid, for example ... 

Atophan (or cihchophen) may be prepared by condensing equimolecular proportions of benzaldehyde, aniline and pyruvic acid in alcoholic solution ... 

This is an example of the Doebner synthesis of quinoline-4-carboxylic acids (cinchoninic acids) the reaction consists in the condensation of an aromatic amine with pyruvic acid and an aldehj de. The mechanism is probably similar to that given for the Doebner-Miller sj nthesis of quinaldiiie (Section V,2), involving the intermediate formation of a dihydroquinoline derivative, which is subsequently dehydrogenated by the Schiff s base derived from the aromatic amine and aldehyde. 

Pyruvic acid is conveniently prepared by the distillation of tartaric acid with a dehydrating agent, such as potassium bisulphate ... 

If the atophan does not crystallise—this is rarely the case unless pyruvic acid which has been standing for some time is employed—pour the reaction mixture into a solution of 2a g. of potassium hydroxide in 1 litre of water, and extract the resulting solution two or three times with ether. Place the ether extracts in the ETHER RESIDUES bottle. Treat the aqueous layer with 70 ml. of glacial acetic acid with vigorous stirring. Allow to stand for several hours and collect the crude atophan by filtration with suction. 

The pyruvic acid (28.8 g, 0.10mol) was dissolved in 1 NNaOH (300 ml) and stirred at 0 "C. A solution of 30% HjOj (11.3 ml, 0.10 mol) was added dropwise. The solution was stirred for 1 h at 5 C and then acidified with dil. HCl. The precipitate was collected by filtration, washed with water, dried and recrystallizcd from hcxanc-EtOAc to yield 22.2 g (8,5% yield) of the product. 

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

IS the oxidation of lactic acid to pyruvic acid by NAD and the enzyme lactic acid coenzyme NAD ... 

Enzyme catalyzed reductions of carbonyl groups are more often than not com pletely stereoselective Pyruvic acid for example is converted exclusively to (5) (+) lactic acid by the lactate dehydrogenase NADH system (Section 15 11) The enantiomer... 

The enzyme is a single enantiomer of a chiral molecule and binds the coenzyme and substrate m such a way that hydride is transferred exclusively to the face of the carbonyl group that leads to (5) (+) lactic acid Reduction of pyruvic acid m the absence of an enzyme however say with sodium borohydride also gives lactic acid but as a racemic mixture containing equal quantities of the R and S enantiomers... 

In spite of the number of different structural types lipids share a common biosyn thetic origin m that they are ultimately derived from glucose During one stage of car bohydrate metabolism called glycolysis glucose is converted to lactic acid Pyruvic acid IS an intermediate... 

L Glutamic acid is not an essential ammo acid It need not be present m the diet because animals can biosynthesize it from sources of a ketoglutaric acid It is however a key intermediate m the biosynthesis of other ammo acids by a process known as transamination L Alanine for example is formed from pyruvic acid by transamination from L glutamic acid... 

In transamination an amine group is transferred from L glutamic acid to pyruvic acid An outline of the mechanism of transamination is presented m Figure 27 4... 

L-tyrosine phenol + pyruvic acid + NH P-tyrosinase Erwinia herbicola ... 

The reaction of hydroxylamine with an a,/3-unsaturated pyruvic acid (533) produced (534) (76TL1825). Hydroxylamines reacted with the nonconjugated ketoalkene (535) to produce (536) (73T2683). 

BAMBERGER Benzolriazine Synthesis From pyruvic acid hydrazone 2 and aryldiazoamine salts 1... 

PICTET SPENGLER Isoquinollne Synthesis Isoquinoline synthesis ol phenethylammes and pyruvic acid derivatives... 

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