Pyruvate ion

Pyruvic acid is an intermediate in the fermentation of grains. During fermentation the enzyme pyruvate carboxylase causes the pyruvate ion to release carbon dioxide. In one experiment a 200.-mL aqueous solution of the pyruvate in a sealed, rigid 500.-mL flask at 293 K had an initial concentration of 3.23 mmol-L -l. Because the concentration of the enzyme was kept constant, the reaction was pseudo-first order in pyruvate ion. The elimination of CU2 by the reaction was monitored by measuring the partial pressure of the C02 gas. The pressure of the gas was found to rise from zero to 100. Pa in 522 s. What is the rate constant of the pseudo-first order reaction ... 

This enzyme [EC 4.1.3.18] catalyzes the reversible car-boxylation of 2-acetolactate with carbon dioxide to form two pyruvate ions. Thiamin pyrophosphate is a required cofactor. 

Glycine Glycinate ion Glycylglycine Glycylglycinate L(+)-Lactic acid L(+)-Lactate ion a-Lactose p-Lactose DL-Leudne L-Leucine L-Leucinate ion L-Malic acid L-Malate ion a-Maltose p-Maltose Methanol L-Methionine Oxaloacetic acid Oxaloacetate ion Palmitic acid Pyruvic acid Pyruvate ion 2-Propanol Succinic acid Succinate ion Sucrose dl-Valine L-Valine L-Valine ion L-Valinate ion Water... 

The glycolysis pathway is a prominent reaction sequence featured in texts and treatises on biochemistry and microbiology, according to the previously cited Chapter 3, and an abbreviated version is also sometimes presented, for instance, by Boik (1996). To reiterate, the primary product of glycolysis is pyruvic acid, CH3COCOOH, which may also be represented as the pyruvate ion, or CH3COCOO. The pyravic add or pyruvate further reacts to form carbon dioxide and watCT, or... 

Scheme 5 Mechanism of the transamination reaction involving Fe, 2-aminomethylpyridine and pyruvate ion...

The ratio of the concentrations of the carboxylate ion and the carboxylic acid will be approximately 1000 1. That is, carboxylic acids will exist primarily as carboxylate salts at physiological pH. For example, pyruvic acid exists primarily as pyruvate ion at physiological pH. 

The oxidation of DL-serine by chromium(VI) proceeds via 2-amino-3-oxopropanoic acid, which is formed in the initial slow step. A mechanism has been proposed for the chromium(VI) oxidation of gallic acid (using potassium dichromate), which gives a trinuclear complex of chromium(III) containing OH and O2 bridges and a pyruvate ion ligand. The oxidation of perchloric acid-catalysed N, A—dimethylformamide (DMF) by chromium) VI) is first order in both Cr(VI) and DMF the order with respect... 

Fig. 4.13 The reactions of glycolysis, in which glucose is partially oxidized by nicotinamide adenine dinucleotide (NAD, Atlas N4) to pyruvate ion.

In the next step, FDP is broken into two three-carbon units, dihydroxyacetone phosphate (1,3-dihydroxypropanone phosphate, CH20HC0CH20P03, 5) and glyceraldehyde-3-phosphate (6), which exist in mutual equilibrium. Only the glyceraldehyde-3-phosphate is oxidized by NAD to pyruvate ion, with formation of two ATP molecules. As glycolysis proceeds, all the dihydroxyacetone phosphate is converted to glyceraldehyde-3-phosphate, so the result is the consumption of two NAD molecules and the formation of four ATP molecules per molecule of glucose. 

In cells that are deprived of O2, pyruvate ion is reduced to lactate ion, CH3CH(0H)C02 (7) by NADH. Very strenuous exercise, such as bicycle racing, can decrease sharply the concentration of Oj in muscle cells, and the condition known as muscle fatigue results from increased concentrations of lactate ion. 

The further oxidation of carbon derived from glucose begins with a reaction between pyruvate ion, NAD , and coenzyme A (CoA, Atlas N6) to give acetyl CoA, NADH, and CO2. Acetyl CoA is then oxidized by NAD and flavin adenine dinucleotide (FAD, Atlas N7) in the citric acid cycle (Fig. 4.14), which... 

The elimination of carbon dioxide from pyruvate ions by a decarboxylase enzyme was monitored by measuring the partial pressure of the gas as it was formed in a 250 cm flask at 293. In one experiment, the partial pressure increased from 0 to 100 Pa in 522 s in a first-order reaction when the initial concentration of pyruvate ions in 100 cm of solution was 3.23 mmol dm" . What is the rate constant of the reaction ... 

The mechanism of the osmium-tetroxide-catalysed oxidation of glycollic and lactic acids has been reported, the rate being independent of oxidant concentration. Evidence is presented for complex formation, and glyoxalate and pyruvate ions are postulated as intermediates. 

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