Pyruvic acid labelled with

The ability of the rat to use lactate, pyruvate, and D-glucose to equal extents in the synthesis of 1-naphthyl D-glucosiduronic acid was demonstrated by Packham and Butler.158 The lactate and pyruvate were labeled with C14 at the carboxyl carbon lactate labeled at Cl and C2 was also used and the D-glucose was uniformly labeled. D-Glucuronate-C14 was utilized for D-glucuronic conjugation on oral administration, but was twenty times as effective after intraperitoneal injection. 

A peptide from pyruvate kinase labeled with oADP (55) and one from ferre-doxin-NADP reductase labeled with oNADP (75) have been isolated and characterized. These are exceptions. Despite the large number of papers describing the kinetics of affinity labeling by periodate-oxidized nucleotides, there are very few reports of the identification of particular amino acids labeled by these reagents within determined peptide sequences. For enzyme products other than a Schiff base reducible by NaBHU, the instability of the products in the proteolytic digests of modified enzymes under conditions of peptide purification has precluded isolation of labeled peptides in most cases. 

If the methyl carbon atom of pyruvate is labeled with which of the carbon atoms of oxaloacetate would be labeled after one turn of the citric acid cycle (See the lettering scheme for oxaloacetate in Figure 17.1 in this book.) Note that the new acetate carbons are the two shown at the bottom of the first few structures in the cycle, because aconitase reacts stereospecifically. 

Treatment of 9-(/ -D-ribofuranosyluronic acid)adenine with diphenylphosphoro-chloridate and orthophosphate or tripolyphosphate yields (62) and (63), which, although unstable, inhibit rabbit AMP aminohydrolase and pyruvate kinase, respectively, with behaviour characteristic of active-site-specific reagents.98 Adenylate kinases from several sources are inactivated by iV6-[2- and 4-fluorobenzoyl]-adenosine-5 -triphosphates, with kinetics characteristic of active-site labelling, although these compounds were without effect on yeast hexokinase and rabbit pyruvate kinase.99... 

Mitomycins.—Support for the derivation of mitomycin (152) from a point along the shikimate pathway comes from the pattern of incorporation of glucose and, particularly, that of incorporation of pyruvic acid. Pyruvic acid was deduced to provide C-5,65 C-6, and C-6a cf. Vol. 6, p. 45), with C-5 corresponding to C-3 in pyruvic acid. Moreover, D-[4-l4C]erythrose labelled C-7 in (152).65... 

As for human cells or enkaryotes, the metabolic path or seqnence involves the conversion of glucose by what is labeled glycolysis. In a series of ten steps there is first produced a compound called pyruvic acid or pyruvate (the latter designating a so-called salt or componnd of pyruvic acid). In the presence of oxygen, this is fnrther converted to carbon dioxide and water in what is variously called the tricarboxylic acid cycle, or citric acid cycle, or Krebs cycle. The overall operation may be conveniently called aerobic glycolysis, with each step requiring a particnlar enzyme, and most usually requiring snpportive reactions. 

Although a great number of alkaloids having a /8-carboline structure have been found in nature, very few reports have been published about their biogenesis, and these are concerned only with the plant material. From among the alkaloids mentioned above only harman (180) and 4,5-dihydrocanthin-6-one (181) were demonstrated in feeding experiments with H- and C-labeled precursors to be derived biosynthetically from tryptophan. In the case of harman, tryptamine is probably condensed with pyruvic acid to give l-methyl-l,2,3,4-tetrahydro-j8-carboline-l-carboxylic... 

A study of the kinetics of the labeling of alanine show that its rate of labeling reaches a maximum as soon as the intermediates of the carbon reduction cycle are saturated with C . Since no secondary products of carbon photosynthesis such as sucrose are approaching saturation at this time (3-5 minutes), it appears that alanine is formed directly from intermediates of the cycle. Presumably, alanine is formed from PGA by the transamination of pyruvic acid derived from phosphoenolpyruvic acid which in turn is derived from PGA [Eq. (28)]. 

Pyruvate can be labeled either in the carboxylic (Hwang et al. 1986 Takahashi et al. 1990) or in the 3-position (Bjurling et al. 1988 Ropchan and Barrio 1984 Cohen et al. 1980). Pyruvate is a versatile compound for further transformations to aromatic amino acids and to lactic acid (Kloster and Laufer 1980 Bjurling and Langstrbm 1989 Cohen et al. 1980). Some aliphatic amino acids have been labeled with R C employing enzymatic and combined chemo-enzymatic methods (Antoni et al. 1997, 2001 Barrio et al. 1982b Cohen et al. 1982 Kaneko et al. 1999 Svard et al. 1990) as exemplified in Pig. 41.31 and 41.32. 

Having chorismic acid available with a stereospecific label in the side chain methylene group we then proceeded to determine the steric course of the anthranilate synthase reaction. The pyruvate generated in the reaction in the presence of H2O (Fig. 19) was oxidized to acetate and analyzed for its chirality. An F value of 44.5 (19% e.e. indicated that the protonation had occurred on the face. This stereochemistry is probably of no mechanistic significance, but it contrasts with that seen in virtually all the reactions in which a proton or other electrophile is added at the methylene carbon of PEP. 

The degradation of PLA by hydrolytic scission of ester linkages yields lactic acids. Lactic acid is a natural product associated with muscular construction in animals and humans, which can be decomposed by the body s normal metabolic pathways. In the body, lactic acid is converted to pyruvic acid and enters the tricarboxylic acid cycle to yield carbon dioxide and water. Using carbon-labeled PLA, no significant amount of accumulation of degradation products... 

Fluorometric HPLC analysis is currently the most sensitive and reliable method for quantitative detection of Sia in the pmol range. In this analysis, a free form of various Sia species is labeled with the fluorescent dye l,2-diamino-4,5-methylene-dioxybenzene (DMB), and fluorometrically analyzed on HPLC [62, 63]. DMB is a reagent which specifically reacts with a-keto acids, and detects not only Sia but also typical a-keto acids such as pyruvate and a-ketoglutarate. Huorometric HPLC analysis consists of the following steps step 1, acid hydrolysis of sialoglycoconjugates to release free Sia step 2, fluorescent labeling of released Sia with DMB step 3, separation and quantification of DMB-labeled Sia on HPLC. 

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