Synthesis and function of (2'-5')An: inhibition of (2'-5')An synthetase by heparin and the use of heparin-agarose for partial purification of (2'-5')An synthetase from rabbit reticulocyte lysates.

Heparin, but not a number of other acid mucopolysaccharides, inhibits (2'-5')An synthetase partially purified from rabbit reticulocytes. The effect of heparin was apparent at 10 micrograms/ml (21%). Maximum inhibition was observed at 200 micrograms/ml (80%). At the latter concentration, the dsRNA-dependent (2'-5')An synthetase activity was inhibited 80% whereas the dsRNA-independent enzyme activity was inhibited only 30%. The formation of the dimer, trimer, tetramer and high oligomers of (2'-5')An was inhibited to the same extent with the addition of heparin. Heparin covalently bound to agarose beads was shown to be a useful affinity resin for the purification of (2'-5')An synthetase from rabbit reticulocyte lysates.