[Enzymatic synthesis of beta-NAD+ selectively marked with tritium at adenine and its use for determining the activity of poly(ADP-ribose) polymerase].

A method of preparation of tritiated beta-HA [symbol: see text]+ from (adenine-2,8-(3)H)ATP and nicotinamide mononucleotide is suggested. This method is based on the baker's yeast (Saccharomyces cerevisiae) enzyme nicotinamide nucleotide adenylyltransferase. Experimental conditions for a nearly complete conversion of labeled ATP to NAD were determined. The tritiated NAD prepared by this method can be used in the quantitative assay of the chromatin enzyme poly(ADP-ribose) polymerase.