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Reduction of pyruvic acid

Biological reduction of pyruvic acid catalyzed by the enzyme... [Pg.300]

The enzyme is a single enantiomer of a chiral molecule and binds the coenzyme and substrate m such a way that hydride is transferred exclusively to the face of the carbonyl group that leads to (5) (+) lactic acid Reduction of pyruvic acid m the absence of an enzyme however say with sodium borohydride also gives lactic acid but as a racemic mixture containing equal quantities of the R and S enantiomers... [Pg.735]

As we have seen a stereoselective reaction is one in which there is a preponderance of one isomer irrespective of the stereochemistry of the reactant. The enzymatic reduction of pyruvic acid is stereoselective when the chiral molecules of the enzyme complexes with achiral pyruvic acid, they given a preponderance of one form of pyruvic acid-enzyme complex which then gives a single form of lactic acid. [Pg.148]

On the other hand a stereospecific reaction is one in which a particular stereoisomeric form of the reactant reacts to give a stereoisomeric form of the product. The enzymatic reduction of pyruvic acid is not stereospecific because the reactant can not existin stereoisomeric form. Therefore, all reactions that are stereospecific are necessarily stereoselective but not all stereoselective reactions are stereospecific. [Pg.149]

In marked contrast, nature s reducing agent, reduced nicotinamide adenine dinucleotide (NADH), delivers hydride in a stereospecific manner because it is a cofactor in an enzyme-catalysed reaction. For example, reduction of pyruvic acid to lactic acid in vertebrate muscle occurs via attack of hydride to produce just one enantiomer, namely (5)-lactic acid. [Pg.96]

It can now be seen that, in the enzymic reduction of pyruvic acid to lactic acid, hydride is delivered to the Re face of the pyruvic acid. [Pg.97]

Figure 12.39 Reduction of Pyruvic Acid into Lactic Acid... Figure 12.39 Reduction of Pyruvic Acid into Lactic Acid...
Fig. 15a, b. Biocatalyzed tranformations coupled to the regeneration of cofactors a) reduction of C02 to formate through regeneration of acetyl-CoA b) reduction of pyruvic acid to lactic acid by regeneration of NADH cofactor... [Pg.177]

When searching for intermediates in a chemical reaction it is useful to examine the reaction in both the forward and reverse directions. The reduction of pyruvic acid by dihydroflavin is the retrograde of the... [Pg.102]

This reaction is completely enantioselective. For example, reduction of pyruvic acid with NADH catalyzed by lactate dehydrogenase affords a single enantiomer of lactic acid with the S configuration. NADH reduces a variety of different carbonyl compounds in biological systems. The configuration of the product (/ or S) depends on the enzyme used to catalyze the process. [Pg.734]

The last step of glycolysis is reduction of pyruvic acid to lactic acid. (The reducing agent is, incidentally, an old acquaintance, reduced nicotinamide adenine... [Pg.1172]

As an example, let us consider the substrate for lactate dehydrogenase—an enzyme which catalyses the reduction of pyruvic acid to lactic acid (Fig. 4.7). [Pg.31]

Furthermore, the latter conversion reaction, the hydrogen reduction of pyruvic acid to lactic acid, or pyruvate to lactate, would be the controlling step in the metabolism of cancer cells. It is catalyzed by the enzyme lactate dehydrogenase, as previously noted, and if an effective inhibitor or catalyst poison can be found that is selective to this particular step, it could concdvably suppress the metabolism of cancer cells. [Pg.157]

Besides several diastereoselective heterogeneous catalytic hydrogenations [1-3] only two enantioselective hydrogenation reactions are known the reduction of p-keto-esters with Raney-nickel modified by tartaric acid and of pyruvic acid esters with Pt modified by cinchona alkaloids. Garland and Blaser [4] described the reduction of pyruvic acid ester as a "ligand-accelerated" reaction with the adsorption of the modifier new active sites are generated on the catalyst surface. On these new centers the selective reaction is faster and the increased reaction rate is accompanied by greater enantioselectivities. [Pg.99]

Lactams, 803 Lactase, 993 Lactic acid, 737, 1015 biological oxidation of, 602 (5 ) enantiomer by enzymic reduction of pyruvic acid, 681-682,1015 Lactones, 758-759, 788 formation of... [Pg.1231]

Some special methods of enantioselective electrochemical reactions should be mentioned. D-Alanine was prepared with an ee close to 100% using the electrochemical reduction of pyruvic acid using an electrode on which amino acid oxidase and electron mediator were immobilized... [Pg.271]

The reduction of pyruvic acid by Eu(II) is reported by Konstantatos et al. (1982) to occur through a complex rate law involving backward reaction of the Eu(III) product with the organic radical species formed in the initial reaction ... [Pg.384]

Biological reduction of pyruvic acid, catalyzed by the enzyme lactate dehydrogenase, gives (+)-lactic acid, represented by the Fischer projection shown. What is the configuration of (+)-lactic acid according to the Cahn-Ingold-Prelog R-S notational system ... [Pg.298]


See other pages where Reduction of pyruvic acid is mentioned: [Pg.321]    [Pg.307]    [Pg.281]    [Pg.176]    [Pg.104]    [Pg.2547]    [Pg.2550]    [Pg.32]    [Pg.276]    [Pg.276]    [Pg.1233]    [Pg.1042]   
See also in sourсe #XX -- [ Pg.156 ]




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