Reactions of formaldehyde with guanosine.

Formaldehyde reacted with guanosine and the products were assayed using fluorescence spectroscopy at different pHs. The reaction products were fluorescent in alkali only as was found with commercial N-2 methylguanosine. Thus, formaldehyde appeared to react with N-2 of guanosine. The reaction was completed with 30s both at 0 degrees C or at 21 degrees C. The stability of the reaction products was further investigated by the addition of glycine. When formaldehyde was allowed to react with guanosine for 30s, 90% of the fluorescence disappeared when glycine was added suggesting a labile adduct such as a methylol derivative. By contrast, after a 20 h incubation only 20% of fluorescence was abolished with glycine suggesting a stable adduct such as a methylene derivative.