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  • FAQ: How to calculate the molarity of ends?

    Molarity = [(µg/µl) ÷ (base pairs x 650 daltons)] x 2 ends

    Example:
    • Calculate the molarity of ends for a linearized 5 kb vector that has a concentration of 250 ng/µl: [(0.25 µg/µl) ÷ (5000 x 650 daltons)] x 2 = 154 nM
    • Calculate the molarity of ends if you put 50 ng of this vector in a 20 µl ligation reaction:
      50 ng ÷ 20 µl = 0.0025 µg/µl 
      [(0.0025 µg/µl) ÷ (5000 x 650)] x 2 = 1.54 nM
    • Determine the amount of a 1 kb insert needed to achieve a 3:1 insert:vector ratio:
      3 X 1.54 nM = 4.62 nM 
      [(X µg/µl) ÷ (1000 x 650)] x 2 = 4.62 nM 
      0.0015 µg/µl x 20 µl = 0.03 µg = 30 ng
    • Does this reaction fall within the optimal range of 1–10 µg/ml?
      (50 ng vector + 30 ng insert) ÷ 20 µl = 4 µg/ml