2′,5′-Oligoadenylate and 2′,5′-oligoadenylate phosphodiesterase in human plasma

2′,5′-Oligoadenylate and 2′,5′-oligoadenylate phosphodiesterase activity were detected in the human plasma and serum by sensitive radioimmuno assays. The phosphodiesterase in the serum degraded 20 nM of added 2′,5′-oligoadenylate in less than 1 hr. Addition of EDTA in the blood sample inhibited the phosphodiesterase activity completely and allowed the measurement of low levels of 2′,5′-oligoadenylate. The concentration in the plasma from healthy people was in the range of 0.03 to 0.3 nM.