4.6.1.21 putrescine enhances activity against poly(C) and yeast RNA 134566 4.6.1.21 spermidine enhances activity against poly(C) and yeast RNA, reverses inhibition by poly(G) by removal of inhibitor from the enzymes surface 134566 4.6.1.21 spermine enhances activity against poly(C) and yeast RNA, reverses inhibition by poly(G) by removal of inhibitor from the enzymes surface 134566