The in vitro demonstration of soluble RNA (sRNA) ethylase activity of high speed supernatant fractions from a variety of mouse tissues is presented, including an analysis of the enzymatic product. Studies with magnesium indicate that effects upon the sRNA secondary structure are involved in sRNA alkylation. Polyadenylic acid, polyuridylic acid, polyinosinic acid, and polyadenylic acid + polyuridylic acid are not used as substrates by a crude yeast cell fraction.
Embryonic and neoplastic liver are more active in ethylating Escherichia coli sRNA than is normal adult liver. The most extensively ethylated nucleotide in sRNA is guanylic acid.
This investigation was supported in part by an allocation from USPHS Grant No. 1 RO1 CA 10476-01, American Cancer Society Grant E-438 (Janice M. Blood Memorial Grant), and USPHS General Research Support Grant #FR-05545 to The Jackson Laboratory, Bar Harbor, Maine.