D -Lactate dehydrogenase

In a related approach, Adam ef al. used glycolate oxidase with D-lactate dehydrogenase for the deracemization of a wide range of racemic a-hydroxy acids (20) (Figure 5.13) [23]. 

Adam, W., Lazarus, M., Saha-Moller, C.R. and Schreier, P. (1998) Quantitative transformation of racemic 2-hydroxy acids into (R)-2-hydroxy acids by enantioselective oxidation with glycolate oxidase and subsequent reduction of 2-keto acids with D-lactate dehydrogenase. Tetrahedron Asymmetry, 9 (2), 351-355. 

The successful synthetic application of this electroenzymatic system has first been shown for the in-situ electroenzymatic reduction of pyruvate to D-lactate using the NADH-dependent D-lactate dehydrogenase. Electrolysis at — 0.6 V vs a Ag/AgCl-reference electrode of 50 mL of a 0.1 M tris-HCL buffer of pH 7.5 containing pentamethylcyclopentadienyl-2,2 -bipyridinechloro-rhodium(III) (1 x 10 3 M), NAD+ (2 x 10 3 M), pyruvate (2 x 10 2 M), 1300 units D-lactate dehydrogenase (divided cell, carbon foil electrode) after 3 h resulted in the formation of D-lactate (1.4 x 10 2 M) with an enantiomeric excess of 93.5%. This means that the reaction occurred at a rate of 5 turnovers per hour with respect to the mediator with a 70% turnover of the starting material. The current efficiency was 67% [67],... 

StoU VS, Manohar AV, Gillon W, Mac Farlane EL, Hynes RC, et al. 1998. A thioredoxin fusion protein of VanH, a d-lactate dehydrogenase from Enterococcus Faecium cloning, expression, purification, kinetic analysis, and crystallization. Protein Sci 7 1147-1155. 

IMIDAZOLEACETATE HYDROXYLASE ISOVALERYL-CoA DEHYDROGENASE KYNURENINE 3-HYDROXYLASE d-LACTATE DEHYDROGENASE (CYTOCHROME)... 

ISOTOPE EXCHANGE AT EQUILIBRIUM d-LACTATE DEHYDROGENASE (CYTO-... 

This system has been successfully applied to the in-situ electroenzymatic reduction of pyruvate to D-lactate using the NADH-dependent D-lactate dehydrogenase or the reduction of 4-phenyl-2-butanone to (5)-4-phenyl-2-butanol using the NADH-dependent horse liver alcohol dehydrogenase (HLADH) with high enantioselectivity (Fig. 22.4) [65]. 

Dehydrogenases Glutathione reductase Acyl-CoA dehydrogenases Succinate dehydrogenase D-Lactate dehydrogenase... 

The flavoenzyme D-lactate dehydrogenase from yeast has been reported to contain zinc (134). An apoenzyme can be prepared and reactivated by Zn2+ or Co2+ (135). When yeast is grown in the presence of added Co2+, a Co(II) enzyme is synthesized. The biosynthetic Co(II) enzyme was found to have different catalytic properties compared to the enzyme reactivated from the apoenzyme (136). Only rather fragmentary data have been published on this subject, and the differences in cobalt binding obtained by the two methods of preparation are unknown. 

Avramescu et al. [24] d-Lactate Wines D-Lactate dehydrogenase/with NAD+ deposited onto the surface of the electrode and covered with polyethyleneimine-Nafion membrane Carbon electrode, modified with an insoluble salt of Meldola s Blue/-50mV vs. Ag/ AgCl Meldola s Blue... 

N. Bernard, K. Johnson, J. J. Holbrook, and J. Delcour, D175 discriminates between NADH and NADPH in the coenzyme binding site of Lactobacillus delbrueckii subsp. bulgaricus D-lactate dehydrogenase, Biochem. Biophys. Res. Commun. 1995, 208, 895-900. 

HL-ADH horse liver alcohol dehydrogenase Y-ADH yeast alcohol dehydrogenase FDH formate dehydrogenase D-Lactate DH D-lactate dehydrogenase ... 

C. Vinals, X. De Bolle, E. Depiereux, and E. Feytmans, Knowledge-based modeling of the D-lactate dehydrogenase three-dimensional structure, Proteins 1995, 21, 307-318. 

R)-2-Hydroxy-4-phenylbutyric acid was produced continuously in an enzyme membrane reactor by enzymatic reductive animation of the a-keto acid with d-lactate dehydrogenase coupled with formate dehydrogenase (FDH) for regeneration of NADH. Reactor performance data matched a kinetic reactor model (Schmidt, 1992). 

In studies with an FAD-dependent D-lactate dehydrogenase from Megaspheria elsdenii, Ghisla and Mayhew (31) noted that some of the enzyme molecules purified as an inactive, orange form. The color was imparted by an altered FAD derivative, an 8-hydroxyFAD, XVI,... 

Fig. 3 Preparation of D-lactate from pyruvate catalyzed by d-LDH (D-lactate dehydrogenase) using formate/FDH for the regeneration of NADH...

This system has been efficiently applied in the in situ electroenzymatic reduction of pyruvate to D-lactate by means of the NADH-dependent D-lactate dehydrogenase (Fig. 23). Using pentamethylcyclopentadienyl-2-2 -bipyridinechloro-rhodium(III) ([Cp Rh(bpy)Cl]Cl) as redox catalyst, D-lactate was formed with an ee value of 93.5% after 3 h at a rate of five turnovers per hour [112]. 

Three types of lactate dehydrogenase are found in yeast, which may be considered as metal-containing flavoproteins. These are L-lactate cytochrome c reductase or cytochrome b, D-lactate dehydrogenase, which is found in anaerobic yeast, and D-lactate cytochrome c reductase, which is associated with the mitochondria of aerobic cells. 

Soluble D-lactate dehydrogenases with enzymic properties similar to those of the D-2-hydroxyacid dehydrogenase of anaerobic yeast have been isolated from rabbit kidney mitochondria (333-334) and from a species of Mycohacterium (335). It is not clear whether these enzymes are metal-containing flavoproteins. 

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