MICROMETHOD FOR DETERMINING ADENOSINE-DEAMINASE AND PURINE NUCLEOSIDE PHOSPHORYLASE ACTIVITY IN CELLS FROM HUMAN PERIPHERAL-BLOOD

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 [8-14Clinosine, 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-1 mg-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 immunodeficiency and adenosine deaminase deficiency has been identified. © 1978.