DIAPHORASE

Использование

Diaphorase from Clostridium kluyveri, or Lipoyl dehydrogenase, has been used in a study to assess the protein-protein interactions in assembly of lipoic acid on the 2-oxoacid dehydrogenases of aerobic metabolism. Lipoyl dehydrogenase has also been used in a study to investigate the redox regulation of tyrosine nitration and 3-nitrotyrosine reduction by antioxidants.

Биохимия/физиол Действия

Diaphorase catalyzes the oxidation of either β-NADH or β-NADPH in the presence of an electron acceptor such as methylene blue or 2,6-dichlorophenolindophenol. Diaphorases which are specific for either β-NADH or β-NADPH are known. The pig heart enzyme of Straub seems to have native diaphorase (β-NADH specific) as well as lipoic and lipoamide dehydrogenase activities. It is reported to be a single protein. However, Massey reports that diaphorase is probably a denatured lipoamide dehydrogenase. Pre-incubation of the pig heart preparation with Cu2+ reduces the lipoamide dehydrogenase activity and proportionately increases the β-NADH diaphorase activity. In our laboratory, we have demonstrated this copper effect to some degree on the pig heart enzyme, but no appreciable effect was observed on the Clostridium kluyveri or torula yeast preparations. The lipoamide dehydrogenase:diaphorase ratio is a measure of the denaturation.