Abstract
An exoribonuclease has been purified from the cytoplasm of HeLa cells. The enzyme produces 5'-AMP as the only product from poly(A). The degradation proceeds in a 3' to 5' direction, and a 3'-OH terminus is required. In addition to poly(A), the enzyme degrades other synthetic homopolymers as well as natural messenger, and ribosomal RNAs. The enzyme can also degrade the poly(A) tract of messenger RNA. DNA and double-stranded RNA are resistant to the enzyme.
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