Interaction of [4-14C]estradiol and its metabolites with polynucleotides in the presence of peroxidase

Incubation of [4-14C]estradiol with either horseradish peroxidase or uterine preparations resulted in the formation of water-soluble products if certain polynucleotides were also present. It was shown that both systems required hydrogen peroxide and that binding of the steroids occurred more readily with DNA or polyadenylic acid than with RNA or polyuridylic acid. The 14C radioactivity associated with the polynucleotides was present in unidentified metabolites and a small amount of unchanged estradiol. These products were bound weakly and could be removed by mild procedures in contrast to the conjugates formed with albumin or thiols by this system. The significance of the action of peroxidase in the binding of estrogens in rat uterus is discussed.

Structure of the poly(G) polymerase component of the bacteriophage f2 replicase

A rifampicin-resistant poly(G) polymerase has been purified from f2 sus 11-infected cells. The poly(G) polymerase is believed to represent part of the f2 replicase on the basis of several criteria. It is present only in infected cells and shares the characteristic rifampicin resistance of crude f2 replicase activity. Partially purified poly(G) polymerase preparations exhibit replicase activity, synthesizing f2 "lus"strand RNA from denatured, partially double-stranded f2 RNA template. Highly purified poly(G) polymerase preparations, although lacking replicase activity, contain a protein which is electrophoretically identical to the protein product of the viral replicase cistron.