Pyruvate 2-oxoglutarate

Congenital lactic acidosis Lactic, pyruvic, 2-oxoglutaric... 

Some data on specific organic acids in amniotic fluid near term were given by Raiha (1963), who used enzymic and colorimetric methods to determine lactate, pyruvate, 2-oxoglutarate and citrate concentrations in an investigation of neonatal metabolic acidosis. Silicic acid chromatography was also used to demonstrate the presence of citric, lactic and pyruvic acids. Typical concentrations observed were lactate 75.69 21.29 mg (100 ml) pyruvate 0.82 0.40 mg (100 ml) citrate 5.55 1.27 mg (100 ml) and 2-oxoglutarate 0.74 0.33 mg (100 ml) (all near-term). 

Aliphatic acids Formic, acetic, butyric, popionic, malic, citric, isocitric, oxalic, fumaric, malonic, succinic, maleic, tartaric, oxaloacetic, pyruvic, oxoglutaric, maleic, glycolic, shikimic, cis-aconitic, trans-aconitic, valeric, gluconic... 

The catabolism of all 21 amino acids gives rise to only six common intermediates acetyl-CoA, pyruvate, oxoglutarate, succinyl-CoA, fumarate or oxaloacetate (Table 8.10). 

Figure 5.3 Major control points of glycolysis and the TCA cycle. Enzymes I, hexokinase II, phosphofructokinase III, pyruvate kinase IV, pyruvate dehydrogenase V, citrate synthase VI, aconitase VII, isocitrate dehydrogenase VIII, a-oxoglutarate dehydrogenase.

Adenine nucleotides Phosphate (P7) Dicarboxylates/P " exchange 2-Oxoglutarate/malate exchange Pyruvate... 

When his studies on carbohydrate oxidation restarted in Sheffield, Krebs experiments included studies on the anaerobic dismutation of pyruvate by bacteria and various animal tissues. Assuming the role for the dicarboxylic acids postulated by Szent-Gyorgi, the main question was the route by which the carbon atoms of pyruvate were converted to succinate. In May 1936 Krebs had observed that if 2-oxoglutarate was added to pyruvate, the yield of succinate was enormously increased. In his notebook written that year (Holmes, 1993) Krebs postulated ... 

The thallium benzoate and thallium 2-oxocarboxylates are available via the reaction of thallium acetate with benzoic acid or the 2-oxocarboxylic acids, due to the lower values of these acids (benzoic acid 4.22, benzoylformic acid 1.2, 2-oxoglutaric acid 31/5.14, pyruvic acid 2.49) compared to acetic acid (4.76) (167). The free acetic acid is distilled off with water as an azeotrope and the thallium carboxylates are obtained in high purity. 

In a 250 mL flask equipped with a stir bar were introduced 4-methyl-2-oxoglutaric acid 1 (0.5 g, 2.9 mmol), CSA (0.45 g, 2.9 mmol), water (145 mL) and acetaldehyde (128 mg, 2.9 mmol). The pH of the solution was adjusted to 7.6 with 1 m KOH before the addition of pig heart Asp AT (1 mg). The commercial enzyme suspension in 3 M (NH4)2S04 was centrifuged (5 min at 10 000 rpm), the supernatant eliminated and the enzyme pellet dissolved in the reaction mixture. The reaction was stirred slowly at room temperature and monitored by titration of pyruvic acid formed from CSA. 

D. Mandler and 1. Willner, Photosensitized NAD(P)H regeneration systems application in the reduction of butan-2-one, pyruvic, and acetoacetic acids and in the reductive amination of pyruvic and oxoglutaric acids to amino acids,... 

Figure B2(i) The pathway for conversion of proline and alanine in the flight muscle of the tsetse fly the major ATP-generating pathway. Alanine aminotransferase is essential for the proline oxidation pathway in order for glutamate to enter the Krebs cycle as oxoglutarate and pyruvate to be converted to alanine, the end of the pathway. It is assumed that the pathway is the same for the Colorado beetle, but no studies have been reported.

The aspartate and glutamate produced by these reactions, plus those taken up from the lumen, are metabolised to oxaloacetate and oxoglutarate, respectively, as discussed above. The a-NH2 group in these amino acids is transferred to pyruvate to form alanine, which is released and then taken up by the liver, where the NH2 group is converted to ammonia and then to urea. 

Now this reaction is effectively a repeat of the pyruvate acetyl-CoA oxidative decarboxylation we saw at the beginning of the Krebs cycle. It similarly requires thiamine diphosphate, lipoic acid, coenzyme A and NAD+. A further feature in common with that reaction is that 2-oxoglutarate dehydrogenase is also an enzyme complex comprised of three separate enzyme activities. 2-Oxoglutarate is thus transformed into succinyl-CoA, with the loss of... 

The intermediary metabolism has multienzyme complexes which, in a complex reaction, catalyze the oxidative decarboxylation of 2-oxoacids and the transfer to coenzyme A of the acyl residue produced. NAD" acts as the electron acceptor. In addition, thiamine diphosphate, lipoamide, and FAD are also involved in the reaction. The oxoacid dehydrogenases include a) the pyruvate dehydrogenase complex (PDH, pyruvate acetyl CoA), b) the 2-oxoglutarate dehydrogenase complex of the tricarboxylic acid cycle (ODH, 2-oxoglutarate succinyl CoA), and c) the branched chain dehydrogenase complex, which is involved in the catabolism of valine, leucine, and isoleucine (see p. 414). 

Non-essential amino acids are those that arise by transamination from 2-oxoacids in the intermediary metabolism. These belong to the glutamate family (Glu, Gin, Pro, Arg, derived from 2-oxoglutarate), the aspartate family (only Asp and Asn in this group, derived from oxaloacetate), and alanine, which can be formed by transamination from pyruvate. The amino acids in the serine family (Ser, Gly, Cys) and histidine, which arise from intermediates of glycolysis, can also be synthesized by the human body. 

This enzyme [EC 2.6.1.42], also referred to as transaminase B, catalyzes the reversible reaction of leucine with a-ketoglutarate (or, 2-oxoglutarate) to produce 4-methyl-2-oxopentanoate and glutamate. The pyridoxal-phosphate-dependent enzyme will also utilize isoleucine and valine as substrates. However, this enzyme is distinct from that of valine pyruvate aminotransferase [EC 2.6.1.66]. See also Leucine Aminotransferase... 

This enzyme [EC 4.1.3.16], also known as 2-keto-4-hy-droxyglutarate aldolase and 2-oxo-4-hydroxyglutarate aldolase, catalyzes the reversible conversion of 4-hy-droxy-2-oxoglutarate to pyruvate and glyoxylate. Interestingly, the enzyme is reported to be able to act on both stereoisomers. 

The reactions of Eq. 15-19 occur nonenzymatically only under the influence of strong base but dehydrogenases often catalyze similar condensations relatively rapidly and reversibly. Pyruvate inhibits lactate dehydrogenase, 2-oxoglutarate inhibits glutamate dehydrogenase, and ketones inhibit a short-chain alcohol dehydrogenase in this manner.133,693... 

Electron microscopy of the core dihydrolipoyl transacylase from E. coli reveals a striking octahedral symmetry which has been confirmed by X-ray diffraction.306 3073 The core from pyruvate dehydrogenase has a mass of 2390 kDa and contains 24 identical 99.5-kDa E2 subunits. The 2-oxoglutarate dehydrogenase from E. coli has a similar but slightly less symmetric structure. Each core subunit is composed of three domains. A lipoyl group is bound in amide linkage to lysine 42 and protrudes from one end of the domain. 

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