| Popis: |
Treatment of yeast RNA with Kethoxal (β-ethoxy-α-keto-butyraldehyde), followed by periodate cleavage, led to the specific introduction of α-ethoxypropionyl groups onto the guanine amino groups of the RNA. The extent of nitrous acid deamination of the guanines of the acylated RNA was reduced by two-thirds when compared to unmodified RNA. The presence of the acyl groups in the nucleic acid was shown by nuclear magnetic resonance spectroscopy. The acyl nucleotide, N2-α-ethoxypropionylguanosine 5'-phosphate (V) was isolated from a venom phosphodiesterase hydrolysate of the RNA. The use of glyoxal in place of Kethoxal in the above procedure led to a nonspecific formylation of the RNA. A reduction in the extent of deamination by nitrous acid of adenine, cytosine, and guanine was noted. This contrasts with the results obtained with the same conditions at the base or deoxynucleoside level, at which specificity for guanine was observed. Treatment of adenine with glyoxal and periodate in the presence of acid, however, afforded N6-formyladenine (IVa). |
