Solubility: Soluble in distilled water or dilute buffer
Stability: -20° C; -4° F
Activity: 7 U/mg solid
Protein: 19-22%
Unit Definition
The amount of enzyme which catalyzes the oxidation of one micromole NADH per minute at pH 6.5 and 25°C.
Assay Method
The assay of lipoamide dehydrogenase is based on the method of Massey, et al. The decrease in the absorbance at 340 nm, caused by the oxidation of NADH, is a measure of the enzyme activity. Note: DL-8,6-Thioctic Acid is the same as DL-a-Lipoic Acid and the same as DL-1,2-Dithiolane-3-pentanoic Acid.
Applications
The enzyme occurs in mammalian and microbial cells and it catalyzes a number of reactions which involve NAD+ or NADH. Lipoamide dehydrogenase from porcine heart contains two polypeptide chains which are similar. It has two molecules of tightly bound flavin adenine dinucleotide (FAD). The molecular weight of the porcine heart enzyme is between 100,000 and 114,000.
