A micromethod for determining adenosine deaminase and purine nucleoside phosphorylase activity in cells from human...

A radiochromatographic method is described for measuring adenosine deaminase and purine nucleoside phosphorylase activity in cells from human peripheral blood. The respective substrates, [8-14C]adenosine or [8-14C]inosine, are converted either to inosine and hypoxanthine or hypoxanthine, respectively. A single simple and rapid chromatographic procedure is used to isolate the products of both reactions. The mean normal activity (nmol h-1mg-1) of ADA for erythrocytes is 63 +/- 24 (+/- 1 S.D.) for leukocytes, 750 +/- 280 and for lymphocytes, 2105 +/- 1170. Corresponding activities for purine nucleoside phosphorylase are 1850 +/- 490, 3665 +/- 1170 and 5890 +/- 2030. With the described methods a further patient with severe combined immuno-deficiency and adenosine deaminase deficiency has been identified.