Aldehyde Dehydrogenase
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This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition
Issued and maintained by the United States Pharmacopeial Convention (USP)
—A white powder. One mg contains not less than 2 enzyme activity units.
Assay: Transfer about 20 mg, accurately weighed, to a 200-mL volumetric flask, dissolve in 1 mL of water, dilute with an ice-cold solution of
bovine serum Albumin (1 in 100) to volume, and mix. Use this solution as the Assay preparation. Dissolve 3.3 g of potassium pyrophosphate, 15 mg of dithiothreitol, and 40 mg of edetate disodium in 70 mL of water, adjust with citric acid monohydrate solution (2.1 in 10) to a pH of 9.0 ± 0.1, dilute with water to 100 mL, and mix to obtain a pH 9.0 buffer. Dissolve an accurately weighed quantity of β-nicotinamide Adenine dinucleotide (β-NAD) in water to obtain a β-NAD solution having a known concentration of about 20 mg per mL. Pipet 0.1 mL of the Assay preparation into a 1-cm spectrophotometric cell. Pipet 0.1 mL of water into a second 1-cm spectrophotometric cell to provide the reagent blank.
Add 2.5 mL of pH 9.0 buffer, 0.2 mL of β-NAD solution, and 0.1 mL of pyrazole solution (0.68 in 100) to each cell, and mix. Stopper the cells, and allow to stand for 2 minutes at 25 ± 1°. Add 0.01 mL of acetaldehyde solution (0.3 in 100) to each cell, and mix. Stopper the cells, and determine the absorbance of the solution obtained from the Assay preparation at a wavelength of 340 nm, using the solution obtained from the reagent blank as the reference. Calculate the change, ΔA, in absorbance per minute for the solution obtained from the Assay preparation, starting at the point when the absorbance and time relationship becomes linear. One enzyme activity unit is de fined as the amount of enzyme that oxidizes 1 μmol of acetaldehyde per minute when the test is conducted under the conditions described herein. Calculate the enzyme activity units in each mg of aldehyde dehydrogenase taken by the formula:
[(2.91)(200)/(6.3)(0.1)(1000)](ΔA/W)
in which ΔA is as defined above and W is the weight, in g, of aldehyde dehydrogenase taken.
