The generation of superoxide anion in the reaction of tetrahydropteridines with molecular oxygen.

Cordycepin (100–200 μg/ml) blocked synthesis of all species of RNA separable by gel electrophoresis and by cellulose chromatography, similarly to actinomycin D, but more efficiently and rapidly. At low concentrations (40–80 μ/ml) cordycepin inhibited predominantly ribosomal RNA synthesis in Physarum, like toyocamycin, another adenosine analog.In nuclear preparations polyadenylylation of RNA was not affected by cordycepin. However, in the presence of cordycepin, no poly(A) RNA was found in the polysome fraction.