An enzyme that catalyzes the conversion of ATP into a series of (2'-5') linked oligoadenylates and pyrophosphate in the presence of double-stranded RNA. These oligonucleotides activate an endoribonuclease (RNase L) which cleaves single-stranded RNA. Interferons can act as inducers of these reactions.

Synonyms: (2'-5')An Polymerase, 2',5' Oligoadenylate Synthetase, 2',5' Oligoadenylate Polymerase, 2-5A Synthetase, 2,5 Oligoadenylate Synthetase, Oligoadenylate Synthetase, 2,5, EC 2.7.7.84, 2',5'-Oligo(A) Polymerase, Synthetase, 2',5'-Oligoadenylate, 2',5'-Oligoadenylate Polymerase, Synthetase, 2,5 Oligoadenylate, 2',5'-Oligo(A) Synthetase, ATP-(2'-5')oligo(A)adenylyltransferase, Polymerase, 2,5 Oligoadenylate, Polymerase, 2',5'-Oligoadenylate, 2,5 Oligoadenylate Polymerase, Oligoadenylate Polymerase, 2,5, 2',5'-Oligoadenylate Synthetase