Determination of the molar absorptivity of NADH.
The molar absorptivity of NADH at 340 nm has been determined by an indirect procedure in which high-purity glucose is phosphorylated by ATP in the presence of hexokinase, coupled to oxidation of the glucose-6-phosphate by NAD+ in the presence of glucose-6-phosphate dehydrogenase. The average value from 85 independent determinations is 6317 liter mol-1 cm-1 at 25 degrees C and pH 7.8. The overall uncertainty is -4.0 to +5.5 ppt (6292 to 6352 liter mol-1 cm-1), based on a standard error of the mean of 0.48 ppt and an estimate of systematic error of -2.6 to +4.1 ppt. Effects of pH, buffer, and temperature on the molar absorptivity are also reported.
D000042:Absorption; D000255:Adenosine Triphosphate; D005069:Evaluation Studies as Topic; D005947:Glucose; D005954:Glucosephosphate Dehydrogenase; D006593:Hexokinase; D006863:Hydrogen-Ion Concentration; D009243:NAD / Q000032:analysis; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature
D009243:NAD; D000255:Adenosine Triphosphate; D005954:Glucosephosphate Dehydrogenase; D006593:Hexokinase; D005947:Glucose