Table 1. pK_a values of cytidine and its derivatives^a.

Nucleoside	pKa
C	4.4 (4.3b)
mC	4.5 (4.4b)
fC	2.4

^aA 0.2 M NaCl solution was used for all pH ranges instead of buffer.

^bData taken from Dawson et al. (32).