Dissolve lyophilized enzyme at one mg/ml in 0.1 M phosphate buffer, pH 7.5.
Immediately prior to use, dilute all enzymes to a concentration of 0.05-0.25 units/ml in 0.1% albumin.
For protein determinations, dissolve enzyme in 0.1 M phosphate buffer, pH 7.5.
Set spectrophotometer to 340 nm and 25°C.
Pipette into each cuvette:
0.1 M Pyrophosphate buffer 1.5 ml 2.0 M Ethanol 0.5 ml 0.025 M NAD 1.0 ml
Incubate in spectrophotometer for 3-4 minutes at 25°C to achieve temperature equilibrium and establish blank rate, if any. At zero time, add 0.1 ml of appropriately diluted enzyme to the cuvette and record the A340 for 3-4 minutes. Calculate the ΔA340/minute from the initial linear portion of the curve.