心肌黄酶 来源于克鲁氏梭状芽孢

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.

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.

Supplied as a lyophilized powder containing trehalose.

“心肌黄酶”这一名称已粗略地应用于几种酶，这些酶在电子受体如亚甲蓝或2,6-二氯苯酚吲哚的存在下，可催化β-NADH或β-NADPH的氧化。这些酶以不同的“单位”以应用于许多不同的检测中。
这些酶是已知对β-NADH或β-NADPH特异的心肌细胞酶。Straub的猪心脏酶可能具有天然心肌黄酶（β-NADH特异性）以及硫辛酸和硫辛酰胺脱氢酶活性。据报道它是一种单体蛋白质。然而，Massey报道“心肌黄酶”可能是一种变性的脂硫辛酰胺脱氢酶。将猪心脏制剂与Cu²⁺进行预孵育，可降低硫辛酰胺脱氢酶活性并呈比例增加β-NADH心肌黄酶活性。在我们的实验室中，我们已经在一定程度上证明了这种对猪心脏酶的铜效应，但在克氏梭菌 或圆酵母制剂中没有观察到明显的效果。硫辛酰胺脱氢酶：心肌黄酶的比率可作为一种变性的量度。

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.