Not available outside of the UK & Ireland.

Application

Diaphorase from Clostridium kluyveri has been used in lactate dehydrogenase assay in gill cells and impregnated on the strip for formate dehydrogenase assay.

Diaphorase is used in various assays to oxidate β-NADH or β-NADPH in the presence of an electron acceptor. Diaphorase from Clostridium Kluyveri has been used for semiquinone generation during benzoquinone reduction. Product D2197 is animal component free.

Biochem/physiol Actions

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.

Packaging

100, 300, 500 units in poly bottle

Physical form

Supplied as a lyophilized powder containing trehalose.

Unit Definition

One unit of diaphorase will oxidize 1.0 micromole of beta-NADH per minute at pH 7.5 at 25 degrees C, with the corresponding reduction of the appropriate electron acceptor.