title: An improved method for purifying 2',5'-oligoadenylate synthetases.
abstract: We describe a new, rapid, and convenient procedure for purifying 2',5'-oligoadenylate synthetases, employing precipitation with ammonium sulfate, fractionation by gel filtration, rapid binding to poly(I) X poly(C) cellulose, and elution with 0.35 M KCl. Unlike previously published methods, the procedure does not require sedimentation of the enzyme at 200,000 X g. Therefore, it is more general and more likely to succeed with synthetases extracted from a variety of cells or tissues, or from different subcellular fractions. We have purified the enzymes from two sources to apparent homogeneity, about 2500-fold from the cytoplasm of HeLa cells in 40% yield and more than 400,000-fold from the cytoplasm of rabbit reticulocytes in 25% yield. The specific activity of the HeLa enzyme is about 4 times higher than reported previously. The physical and functional properties of the pure enzymes are very similar to those reported by others for preparations of 2',5'-oligoadenylate synthetase from rabbit reticulocytes, mouse L cells, and human HeLa cells. A new affinity matrix was prepared by linking periodate-oxidized poly(I) X poly(C) to a hydrazide derivative of finely divided cellulose. Poly(I) X poly(C) cellulose binds about twice as much synthetase as the corresponding amount of poly(I) X poly(C) paper and activates the bound enzyme about three times better.
mesh_terms: D015088:2',5'-Oligoadenylate Synthetase / Q000302:isolation & purification*; D000818:Animals; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D005347:Fibroblasts / Q000201:enzymology; D006367:HeLa Cells / Q000201:enzymology; D006801:Humans; D008722:Methods; D051379:Mice; D011070:Poly I-C / Q000378:metabolism; D011817:Rabbits; D012156:Reticulocytes / Q000201:enzymology; D012995:Solubility; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D015088:2',5'-Oligoadenylate Synthetase; D011070:Poly I-C