The use of bacterial luciferase and a liquid scintillation spectrometer to assay the enzymatic synthesis of NAD+

Abstract

Summary Low levels of NAD+ and the NAD+ synthesizing enzyme ATP:NMN adenylyltransferase can be measured with standard scintillation counting equipment in an assay based on quantitating the light emitted by bacterial luciferase in response to NADH. This assay is 100 to 1000 times more sensitive than the conventional assay based on absorbance at 340 nm. It has been particularly useful for following the purification of ATP/NMN adenylyltransferase, since the small amounts of available enzyme could be assayed in dilute fractions from gel filtration columns or in fractions from polyacrylamide gels.