Modification of Adenine and Cytosine Derivatives with Bromoacetaldehyde

Bromoacetaldehyde reacted with adenosine 5′-phosphate and cytidine more rapidly than chloroacetaldehyde to give 1,N⁶-ethenoadenosine 5′-phosphate and 3,N⁴-ethenocytidine, respectively. The pH-dependence of the rates of these reactions was similar to that of the chloroacetaldehyde modifications reported in the literature; i.e. the reactions proceed smoothly in the pH range of 5 to 7. When applied to polynucleotides, bromoacetaldehyde reacted with adenine and cytosine residues located in single-stranded regions but not with those in double-stranded regions. Guanosine 5′-phosphate reacted with bromoacetaldehyde at pH 7 but only very slowly at pH 5. Bromoacetaldehyde may be useful as a more reactive subtitute for chloroacetaldehyde. Bromoacetaldehyde showed little mutagenic activity when assayed on Salmonella typhymurium TA 100.