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In contrast to the current view that kinetin (N 6-furfuryladenine) is an unnatural and synthetic compound, we have detected it in commercially available DNA, in freshly extracted cellular DNA from human cells and in plant cell extracts by two independent methods. First, we discovered that N6-furforyladenine has electrochemical properties that can be applied for monitoring this modified base by a HPLC/UVIEC method. Second, we have confirmed electrochemical assignments by mass-spectrometric analysis. A pathway of kinetin formation is proposed in which the formation of furfural by oxidative damage of the deoxyribose moiety of DNA is followed by its reaction with adenine residues to form N6-furfuryladenine. Since this modification can lead to mutations, the odd DNA base has to be removed by repair enzymes.

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We have used RNases T1, T2 and A to digest two aminoacyl‐tRNAs, Escherichia coli Phe‐tRNAPhe and E. coli Met‐ tRNAMetm both in the naked forms and in ternary complexes with E. coli elongation factor Tu (EF‐Tu) and GTP. An analysis of the ‘footprinting’ results has led to an interpretation that has localized the part of the three‐dimensional structure of aminoacyl‐tRNA covered by the protein in the ternary complex. In terms of the three‐dimensional structure of tRNA established for yeast tRNAPhe, EF‐Tu covers the aa‐end, aa‐stem, T‐stem, and extra loop on the side of the L‐shaped tRNA that exposes the extra loop.