Pyruvic acid. Table

In addition to the catalysts listed in Table 2, several rhodium(I) complexes of the various diphosphines prepared by acylation of bis(2-diphenylphosphinoethyl)amine were used for the hydrogenation of unsaturated acids as well as for that of pyruvic acid, aUyl alcohol and flavin mononucleotide [59,60]. Reactions were mn in 0.1 M phosphate buffer (pH = 7.0) at 25 °C under 2.5 bar H2 pressure. Initial rates were in the range of 1.6-200 mol H2/molRh.h. 

A few enzymes that might be expected to have PLP at their active sites have instead a prosthetic group consisting of pyruvic acid bound by an amide linkage, a pyruvoyl group (Table 14-4). These and ... 

Pyruvic acid, pK 1 value of 293 Py ruvoyl groups in enzymes, 753 - 755 table 753... 

Table V is also an index to Table I it classifies the compounds according to the functional groups they contain. One frequently wants to examine data on carbonyl compounds, on unsaturated or halogenated ketones, or another more or less specific class of substances, and the purpose of Table V is to simplify searches of this sort. Pyruvic acid appears in Table V both among the ketones and among the carboxylic acids, and Inspection of either group would quickly reveal any closely related compound that appears in this volume.

The characteristic feature of carbohydrate breakdown in cestodes is the production of a range of complex end-products, usually organic acids, even under aerobic conditions (Table 5.4). This contrasts with predominantly aerobic organisms, such as most free-living metazoa, where the end-product of glycolysis is almost exclusively lactic acid formed from pyruvic acid. Lactic acid is produced as a result of rapid muscular contraction carried out essentially under anaerobiosis and its production ensures a rapid expenditure of energy without the limitation due to the rate of diffusion of oxygen. The anaerobic phase is followed by an aerobic phase, where pyruvic acid is metabolised to acetyl-coenzyme A which is in turn oxidised completely to... 

TABLE 13.7 Rates of Hydrogenation of a Mixture of Pyruvic Acid and a-Phenylethylamine over Various Pd-C Catalysts0 ... 

The acid cleavage of a-phenylvinyl diethyl phosphate, which most probably proceeds by an ASj 2 mechanism, was found to be catalyzed by micellar sodium dodecyl sulfate (NaLS) and hexadecyl sulfonic acid (Table 8), whereas that of phosphoenol pyruvic acid was slightly inhibited by cationic and anionic surfactants (Bunton and Robinson, 1969c). The considerably greater rate enhancement by sodium dodecyl sulfate in 0-01m than in 0-10 m acid (Table 8) can reasonably be attributed... 

Diabetic ketoacidosis may produce increased concentrations of acetoacetate, which serves as a chromophore in the Jaffe reaction, thereby increasing the serum creatinine concentration. Other substances in the serum that affect this reaction include glucose, protein, pyruvate, fructose, uric acid, and ascorbic acid (Table 41-3). In... 

In tissues other than the RBC, pyruvate has alternative metabolic fates that, depending on the tissue, include gluconeogenesis, conversion to acetyl-CoA by pyruvate dehydrogenase for further metabolism to CO in the tricarboxylic acid (TCA) cycle, transamination to alanine or carboxylation to oxaloacetate by pyruvate carboxylase (Table 23-1). In the RBC, however, the restricted enzymatic endowment precludes all but the conversion to lactate. The pyruvate and lactate produced are end products of RBC glycolysis that are transported out of the RBC to the liver where they can undergo the alternative metabolic conversions described above. 

Some subaerial plants use a different pathway, involving carboxylation of phosphoenol pyruvic acid (PEP) instead of ribulose diphosphate (the C02 is actually transformed into bicarbonate before incorporation), which subsequently forms a C4 compound, oxaloacetic acid, instead of PGA (Fig. 1.7). Consequently such plants are termed C4 plants. The C4 path is a relatively recent evolutionary development of particular advantage in hot dry climates (see Box 1.10).The PEP cycle effectively transfers C02 to the Calvin cycle, and each cycle confers an isotopic fractionation. Some plants, the CAM plants (see Box 1.10), can use the combined PEP-Calvin cycle path (with some leakage of C02 out of the cell between the cycles) or just the Calvin cycle. The effects of these pathways on the overall isotopic fraction are reflected in the 813C values in Table 5.8. 

Fraction A obtained from the elution of a two-year-old Port wine through Toyopearl gel column with 20% aqueous ethanol was found to be mainly comprised of eight pigments which structural identities were ascertained by LC-MS (Table 1). The number attributed to each compoimd in Table 1 corresponds to the elution order by HPLC in the condition described herein. The three major pigments detected were isolated by semi-preparative HPLC and their structures were fully elucidated by mass spectrometry and NMR. Based on their UV-visible characteristics and structural analysis, these pigments were found to correspond to the pyruvic acid adducts of malvidin 3-glucoside (3A), malvidin... 

Anthocyanin-pyruvic acid adducts are known to be more abundant in Port wines than in red table wines, as seen from previous analysis in our laboratories (data not shown) and as referred by other authors (77). This feature may be related to the higher levels of pyruvic acid expected in fortified wines as a result of a shortened fermentation. In fact, when wine spirit is added in order to stop fermentation, the pyruvic acid concentration is expected to be higher than when the fermentation is allowed to go to dryness. Effectively, the pyruvic acid excreted by the yeast at the beginning of the fermentation is further used in the yeast metabolism (35). Therefore, could favor the formation of anthocyanin-pyruvic acid adducts. 

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