Biochemical activity of murine tissues and recombinant NTPDase1 and NTPDase2.

NTPDase activities of protein preparations were determined by measurement of phosphate release from the respective substrates. Data are expressed as the mean ± SD for specific ATPase (□) or ADPase (■) activities. (A) NTPDase activities ofcd39^+/+ (n = 5) andcd39^−/− (n = 5) mouse lung and heart preparations were measured. (B) NTPDase activity of protein extracts from NTPDase1- or NTPDase2-transfected cells were compared with control cells—untransfected (COS) or those transfected with pcDNA3 empty vector (n = 3 different transfections).