Pseudouridine and N1-Methylpseudouridine Display pH-Independent Reaction Rates with Bisulfite Yielding Ribose Adducts.

In RNA, pseudouridine ( Ψ ) and 5-methylcytidine ( m 5 C ) are located by their differential reactions with NaHSO 3 at pH 5. The pyrimidines were allowed to react with NaHSO 3 , NaN 3 , NaCN, or NaSCN at pH 5 to find that NaHSO 3 was unique in achieving quantitative yields. Pseudouridine reaction selectivity with NaHSO 3 was found at pH 7 supported by the reaction rate constants. The Ψ derivative N1-methylpseudouridine found in mRNA vaccines reacts similarly with bisulfite to yield ribose adducts.