[Energy transfer from tryptophan to 1, N6-ethenoadenosine in frozen aqueous solution]

Mixed aggregates of tryptophan and 1, N6-ethenoadenosine (epsilon Ado) are formed in frozen aqueous solutions at 77 K. In these aggregates one observes a quenching of tryptophan fluorescence by small amounts of epsilon Ado together with a sensitized fluorescence of epsilon Ado. About 70 tryptophan molecules are able to transfer their energy to one epsilon Ado molecule.