Pyruvic acid source

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... 

When grown in a mineral medium containing KDO as the only source of carbon, cells of Aerobacter cloacae can be induced to produce an enzyme that catalyzes the cleavage of KDO to give D-arabinose and pyruvic acid.89 This enzyme was purified 60-fold by Ghalambor and Heath.154 It has a pH optimum of 7, a KM = 6 mM, and an equilibrium constant of 77 mM. The reversible nature of the enzyme reaction can be utilized to synthesize 14C-labelled KDO from D-arabinose plus 14C-pyruvic acid. Cleavage of KDO as catalyzed by KDO aldolase has... 

EC 1.11.1.7) (68) and diphenol oxidase (EC 1.10.3.1) (69) have been identified. The potential role of pyruvic decarboxylase (EC 4.1.1.1) catalyzed reaction as a source of acetaldehyde and other aldehydes in juice was discussed (70). Raymond et al. (71) isolated the decarboxylase from orange juice sections and demonstrated that only 10 to 15% of the enzyme was in an active form. Since the purified enzyme was only active with pyruvic acid and 2-ketobutyric acid of the series of 2-ketoacids examined, they (71) concluded that the direct contribution of orange pyruvic decarboxylase to the orange volatile profile was limited to acetaldehyde and possibly propionaldehyde. 

You have already seen that citric acid is made from acetyl CoA. The acetyl CoA comes in its turn from pyruvic acid. Pyruvic acid comes from many sources but the most important is glycolysis acetyl CoA is the link between glycolysis and the citric acid cycle. The key reaction involves both Co ASH and pyruvate and carbon dioxide is lost. This is an oxidation as well and the oxidant is NAD+. The overall reaction is easily summarized. 

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. 

The photochemical carboxylation of pyruvic acid by this process is endergonic by about AG° = 11.5 kcal mol and represents a true uphill photosynthetic pathway. The carbon dioxide fixation product can then act as the source substrate for subsequent biocatalyzed transformations. For example, photogenerated malic acid can act as the source substrate for aspartic acid (Figure 35). In this case, malic acid is dehydrated by fumarase (Fum) and the intermediate fumaric acid is aminated in the presence of aspartase (Asp) to give aspartic acid. 

It may be observed that, for the cycle to revolve, a supply of oxaloacetic acid is required with which the acetyl-CoA can react. Of course, oxaloacetic acid is being constantly re-formed as each revolution of the cycle is completed, but, nonetheless, it is not surprising to find that many cells, especially in bacteria, take precautions against running out of so essential a primer by having an alternative source of oxaloacetic acid. The alternative source is provided by an enzyme, oxaloacetic decarboxylase which catalyses the direct fixing of carbon dioxide on to pyruvic acid to form oxaloacetic acid as in equation (24) ... 

Organic Acids. The ability of 33 strains of yeast to grow and produce pyruvic acid using dried citrus peel as a substrate was evaluated (22). Debaryomyces coudertii IFO 1381 and Candida utilis IF0 0396 produced yields of pyruvic acid near 82 mg/100 mL after 24 hours of fermentation at 30°C. Fermentation conditions were optimized with respect to nitrogen source (0.5% ammonium sulfate, dibasic phosphate concentration (0.1%), yeast extract concentration (0.01%), calcium carbonate concentration (1.0%), and magnesium sulfate concentration (0.01%). Pretreatment of citrus peel powder with the sodium form of Amberlite IR-120B was observed to enhance pyruvic acid production. Under optimized conditions, a maximum of... 

Alloxane can act as a source of oxomalonic acid under certain conditions,97,98 and 1,3-dimcthyl-substituted alloxane can act as a source of the monomethylamide of oxomalonic acid.96 4-Isobutyl-2-rrilluoromethyl-l,3-oxazol-5(2/7)-one (8) acts as a source of isopropyl-substituted pyruvic acid.99... 

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