Stereospecific reduction of R(+)-thioctic acid by porcine heart lipoamide dehydrogenase/diaphorase.
R(+)-thioctic acid is the naturally occurring cofactor in alpha-ketoacid dehydrogenases. We show both photometrically by NADH+H+ oxidation and by HPLC product analysis that this enantiomer is rapidly reduced by NADH+H+ catalyzed by porcine heart lipoamide dehydrogenase/diaphorase. The racemate exhibits approximately 40% activity as compared to the R(+) form while the S(-) enantiomer photometrically shows little activity and yields no detectable reduced lipoic acid.
Schempp
H
H
Lehrstuhl für Phytopathologie, Labor für Angewandte Biochemie, Technische Universität München.
Ulrich
H
H
Elstner
E F
EF
D000818:Animals; D008058:Dihydrolipoamide Dehydrogenase / Q000378:metabolism*; D009206:Myocardium / Q000201:enzymology*; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D013379:Substrate Specificity; D013552:Swine; D008063:Thioctic Acid / Q000378:metabolism*
D008063:Thioctic Acid; D008058:Dihydrolipoamide Dehydrogenase