DNA and RNA Molecular Weights and Conversions | Thermo Fisher Scientific

Nucleotide Molecular Weights

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Nucleotide	MW (g/mol)
Ribonucleotide Triphosphates (Avg. MW = 499.5)
ATP	507.2
CTP	483.2
GTP	523.2
UTP	484.2
Ribonucleotide Monophosphates (Avg. MW = 339.5)
AMP	347.2
CMP	323.2
GMP	363.2
UMP	324.2
Deoxyribonucleotide triphosphates (Avg. MW = 487.0)
dATP	491.2
dCTP	467.2
dGTP	507.2
dTTP	482.2
Deoxyribonucleotide Monophosphates (Avg. MW = 327.0)
dAMP	331.2
dCMP	307.2
dGMP	347.2
dTMP	322.2

Nucleic Acid Molecular Weight Conversions

Exact M.W. of ssRNA (e.g., RNA Transcript):
M.W. = (An x 329.2) + (Un x 306.2) + (Cn x 305.2) + (Gn x 345.2) + 159ª
An, Un, Cn, and Gn are the number of each respective nucleotide within the polynucleotide.
M.W. calculated is valid at physiological pH.
ªAddition of "159" to the M.W. takes into account the M.W. of a 5' triphosphate.

Exact M.W. of ssDNA (e.g., Oligonucleotides):
M.W. = (An x 313.2) + (Tn x 304.2) + (Cn x 289.2) + (Gn x 329.2) + 79.0ª
An, Tn, Cn, and Gn are the number of each respective nucleotide within the polynucleotide.
ªAddition of "79.0" to the M.W. takes into account the 5' monophosphate left by most restriction enzymes. No phosphate is present at the 5' end of strands made by primer extension.

Approximate M.W.'s of Nucleic Acids:
M.W. of ssRNA = (# nucleotides x 320.5) + 159.0
M.W. of ssDNA = (# nucleotides x 303.7) + 79.0
M.W. of dsDNA = (# nucleotides x 607.4) + 157.9

ssRNA Size and Mass Conversions

Size (nt)	Daltons or g/mol	1 µg equivalent
Size (nt)	Daltons or g/mol	pmol	molecules
20	6,569	152.23	9.17 x 10¹³
100	32,209	31.05	1.87 x 10¹³
300	96,309	10.38	6.25 x 10¹²
500	160,409	6.23	3.75 x 10¹²
1000	320,659	3.12	1.88 x 10¹²
1800	577,059	1.73	1.04 x 10¹²

ssDNA Size and Mass Conversions

Size (nt)	Daltons or g/mol	1 µg equivalent
Size (nt)	Daltons or g/mol	pmol	molecules
20	6,153	162.52	9.79 x 10¹³
100	30,449	32.84	1.98 x 10¹³
300	91,189	10.97	6.6 x 10¹²
500	151,929	6.58	3.96 x 10¹²
1000	303,779	3.29	1.98 x 10¹²
1800	546,739	1.83	1.1 x 10¹²

dsDNA Size and Mass Conversions

Size (nt)	Daltons or g/mol	1 µg equivalent
Size (nt)	Daltons or g/mol	pmol	molecules
20	12,306	81.26	4.89 x 10¹³
100	60,898	16.42	9.89 x 10¹²
300	182,378	5.48	3.3 x 10¹²
500	303,858	3.29	1.98 x 10¹²
1000	607,558	1.65	9.91 x 10¹¹
1800	1,093,478	0.91	5.51 x 10¹¹

Absorbance Units to Nucleic Acid Concentration Conversion

1 A260 dsDNA = 50 µg/ml

1 A260 ssDNA = 37 µg/ml

1 A260 ssRNA = 40 µg/ml

Nucleotide Absorbance Maxima and Molar Extinction Coefficients

Nucleotide	Absorbance Maximum at pH 7.0 (nm)	Molar Extinction Coefficient at pH 7.0
ATP	259	15,400
CTP	271	9,000
GTP	253	13,700
UTP	262	10,000
dATP	259	15,200
dCTP	271	9,300
dGTP	253	13,700
dTTP	267	9,600