Nucleotides molecular weights:

NTP MW(Da) dNTP MW(Da)
ATP 507.2 dATP 491.2
CTP 483.2 dCTP 467.2
GTP 523.2 dGTP 507.2
UTP 484.2 dTTP 482.2
average 499.5 average 487.0
NMP MW(Da) dNMP MW(Da)
AMP 347.2 dAMP 331.2
CMP 323.2 dCMP 307.2
GMP 363.2 dGMP 347.2
UMP 324.2 dTMP 322.2
average 339.4 average 327.0