Fig. 3.

A plasma ecto-nucleotidase assay. a ¹⁴C-ADP catalyzed by potato apyrase, an internal standard. b A standard curve of ADP conversion as a function of apyrase concentration as fitted by a sigmoidal function. c An example of ADPase activity measured in human plasma. The presence of Ap5A, POM1, and POM6 are indicated as above. All lanes contain EHNA that inhibits adenylate deaminase 1. d Diagram of total ADPase activity in human plasma and the corresponding activity that is sensitive to Ap5A, POM1, and POM6. The error bars represent the standard deviation from twelve human subjects (*p value < 0.0001)