Lactic acid biological oxidation

The NAD -NADH coenzyme system is involved in a large number of biological oxidation-reductions. Another reaction similar to the ethanol-acetaldehyde conversion is the oxidation of lactic acid to pyruvic acid by NAD and the enzyme lactic acid dehydrogenase ... 

There are many examples of second-order reactions in biological systems. The enzyme-catalyzed reaction betweeruthe oxidized form of nicotinamide adenine dinucleotide, NAD, with L-lactic acid can be written as follows... 

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... 

Biologically important compounds. Again, mostly nondeterminable at common CPEs are most of amino acids glucose (typically, via the H2O2 release and its subsequent oxidation or reduction in the ampero-metric mode see [180] and Figure 11.4d) and other monosaccharides less-frequent vitamins (A, Bl, B9, B12, D, Kl, and K3), hormones, and steroids lactic acid and lactates and antioxidants (mainly flavanols and flavonoids), plus some bacteria and viruses. 

Enantiomers often behave differently in a biological setting because these properties usually involve a reaction with another chiral molecule. For example, the enzyme lactic acid dehydrogenase will oxidize ( + )-lactic acid to pyruvic acid, but it will not oxidize ( —)-lactic acid (eq. 5.2). 

The stereoselective construction of substituted tetrahydrofurans as enantiomerically pure form is of great interest because many biologically active compounds have such oxygen heterocycles. Fujita et al. developed the synthesis of tetrahydrofuran-3-yl carboxylates 26 via intramolecular oxygenatirm of but-3-enyl carboxylates using lactic acid-derived chiral X -iodanes 25 (Scheme 11) [49, 50]. The enr o-selectivity achieved in this case contrasts with the cxo-selectivity observed in the reaction with conventional oxidizing reagents. The products 26 are obtained in up to 64% ee. 

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