The distinct endoribonuclease activity of L104R and E126D APE1 variants is resistant to RNasin, an RNase inhibitor.

<p>WT APE1, L104R or E126D (1.4 µM) were tested against 25 nM of 5′-γ-³²P-radiolabeled c-<i>myc</i> nts 1705-1792 CRD RNA in a total reaction volume of 20 µl for 25 mins at 37°C. RNasin, at 0.25 to 1 U, was added to the specified samples as denoted. Asterisks indicate cleavage sites generated by L104R and E126D that are resistant to RNasin inhibition.