 
Summary: 52
Primer Notes
1. Primer yield and concentration (approximate ):
1 OD260 of ssDNA 37 µg DNA
A260 value X 37 = µg oligo
µg oligo ÷ Mr = µmol oligo (X 1000 = nmol oligo)
Average nucleotide 325 Daltons
Example: 10 OD260 units of a 20mer in 1 ml 57 nmol/ml 57 µM 57 pmol/µl
Primer yield and concentration (exact):
µg/OD260 = MW (ammonium salt)/extinction coefficient
MW (ammonium salt) = MW (oligo) + [(# of bases 1) X 16.06]
MW (oligo) = [(#A X 313.2) + (#C X 289.2) + (#G X 329.2) + (#T X 304.2) + (#U X 290.2)
+ (#I X 252) + (#N X 309)]  62
Extinction coefficient = (#A X 15.3) + (#C X 7.4) + (#G X 11.8) + (#T X 9.3) + (#U X 10.1) +
(#I X 12.25) + (#N X 10.95)
2. Primer storage:
It is best to store primers at a high concentration at 20°C. Typically, this will mean 50X 100X
(or more) concentrated than used in sequencing or PCR reactions. Thus, it will be necessary to
dilute the primer stock solution before use. Keep the dilute primer at 20°C until it is exhausted.
3. Reconstitution:
