Lactate-dehydrogenase

Similar mechanistic questions arise for lactate dehydrogenase, an enzyme which has been investigated with QM/MM methods by Moliner, Turner and 

As outlined above, Bash et al. concluded that in the similar malate dehydrogenase reaction, proton transfer preceded hydride transfer. 

Up to now, the only limitation in the use of LDH for the recycling of nicotinamide cofactors was related to the strict specificity of the wild-type enzymes toward NAD . 

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Enzyme catalyzed reductions of carbonyl groups are more often than not com pletely stereoselective Pyruvic acid for example is converted exclusively to (5) (+) lactic acid by the lactate dehydrogenase NADH system (Section 15 11) The enantiomer... 

Biochemical oxidation of lactate to pymvate by lactate dehydrogenase is a well-known enzymatic reaction ia metaboHc pathways. 

The absorbance change (AM) at 340 nm can be used to determine the amount of pymvate remaining. The lactate dehydrogenase [9001-60-9] catalyzed reaction can also be used in the reverse direction to measure lactate. The reaction takes place in a buffer of pH 9—10 that neutralizes Hberated H". ... 

L-lactate dehydrogenase semm differentiation of heart cell damage... 

Multienzyme electrodes can increase sensitivity from micromolar to nanomolar detection levels (53,57). In this case the substrate is converted to a detectable product by one enzyme, then that product is recycled into the initial substrate by another enzyme resulting in an amplification of the response signal. For example, using lactate oxidase and lactate dehydrogenase immobilized in poly(vinyl chloride), an amplification of 250 was obtained for the detection oflactate (61). 

Lactate dehydrogenase (from dogfish. Beef muscle)... 

G Wu, A Eiser, B ter Kuile, A Sail, M Muller. Convergent evolution of Trichomonas vaginalis lactate dehydrogenase from malate dehydrogenase. Proc Natl Acad Sci USA 96 6285-6290, 1999. 

FIGURE 19.30 (a) Pyruvate reduction to ethanol in yeast provides a means for regenerating NAD consumed in the glyceraldehyde-3-P dehydrogenase reaction, (b) In oxygen-depleted muscle, NAD is regenerated in the lactate dehydrogenase reaction. 

Jervis used porous silica coated with chemisorbed polyacrylhydrazide for immobilization of adenosine monophosphate (AMP) [117]. After periodate oxidation of its ribose residue the ligand was coupled to the carrier and used for isolation of lactate dehydrogenase from rabbit muscle. The specific capacity was 2 mg of protein/g adsorbent with a ligand content of 10 pmol/g, whereas recovery of enzymatic activity after elution was 85%. Hipwell et al. [118] found that for effective binding of lactate dehydrogenases on AMP-o-aminoalkyl-Sepharose the spacer arm length required at least 4 methylene links. Apparently, a macromolecule of polyacrylhydrazide acts itself like an extended spacer arm and thus allow AMP to bind the enzyme. 

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