Inhibitor of 2',5'-oligoadenylate synthetase induced in human T lymphoblastoid cell line treated with deoxyadenosine, deoxycoformycin and interferon

The effect of deoxyadenosine (dAdo) with deoxycoformycin on the induction of 2',5'-oligoadenylate synthetase by interferon was investigated. After semi-purification through poly(I):poly(C) gel, the activity was similar in control and dAdo-treated cells. However, the activity in the crude extract decreased with rising concentrations of dAdo. On the other hand, the level of 2'-phosphodiesterase, which is also induced by interferon and degrades 2',5'-oligoadenylate, showed no significant change after dAdo treatment. Thus, the crude extract was speculated to contain an inhibitor of 2',5'-oligoadenylate synthetase. Further characterization of the inhibitor revealed that inhibition was not due to dATP accumulation in cells.     

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 healty people was in the range of 0.03 to 0.3 nM.