To provide further verification that the new peak we had observed indicated the formation of 2'/3'-Ala-Ala-esters, we HPLC purified the species responsible for the peak, then lyophilised and digested it with RNAse. The chromatogram of the digested material contained peaks consistent with both 2'-and 3'-Ala-Ala-ester adenosines (Fig. ) when compared to synthetic standards. The region of the chromatogram corresponding to the bis-2',3'-Ala,Ala-diester adenosine standard was quite congested in the digested sample, but very low in intensity. We conclude the new peak to result from the formation of 2'/3'-Ala-Ala-esters. Furthermore, we were able to identify a mass peak corresponding to the 10-mer strand plus three alanine residues by MALDI (Fig. ), which is logically even more likely to include at least one peptide bond.