Two molecular weight forms of human 2',5'-oligoadenylate synthetase have different activation requirements.
Ion-exchange and gel filtration chromatography were used to purify partially a 33,000-dalton (33 kD) 2',5'-oligoadenylate synthetase and a 110,000-dalton (110 kD) 2',5'-oligoadenylate synthetase from HeLa cells treated with alpha-interferon (IFN-alpha). The 33-kD enzyme was optimally activated only when double-stranded RNA was added in 100 to 1000-fold excess of the concentration activating the 110-kD enzyme. Certain double- or triple-stranded RNAs, which were observed to activate the 110-kD enzyme, failed to activate the 33-kD enzyme, even when added at high concentration. The 110-kD enzyme manifested an alkaline pH optimum of 7.5 or more and the 33-kD enzyme an acidic pH optimum of 6.0 or less. The results suggest that intracellular activation of the two forms of 2',5'-oligoadenylate synthetase may occur under markedly different conditions.
D H
DH
Ilson
P F
PF
Torrence
J
J
Vilcek
D015088:2',5'-Oligoadenylate Synthetase / Q000302:isolation & purification / Q000378:metabolism*; D002478:Cells, Cultured; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D004789:Enzyme Activation; D006367:HeLa Cells / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007370:Interferon Type I / Q000494:pharmacology*; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000494:pharmacology; D012270:Ribosomes / Q000201:enzymology
D007370:Interferon Type I; D007527:Isoenzymes; D012330:RNA, Double-Stranded; D015088:2',5'-Oligoadenylate Synthetase