For a sample containing both protein and nucleic acid, theabsorbance measured at a particular wavelength will be the sum ofcontributions from both types of molecule. Using the protein andnucleic acid concentrations you calculated in the previous step,calculate how much of the absorbance of the BSA and E.coliextract comes from protein and how much from nucleic acid, at eachwavelength. HINT: the values in the table provided, are in essence,extinction coefficients with the units(mg/ml)-1cm-1.
| A260 | A280 |
| protein | 0.512 | 0.894 |
| nucleic acid | 22.1 | 10.8 |
There was a question previous to this, and I calculated that myprotein concentration is 0.58 mg/ml and that my nucleic acidconcentration is 0.04 mg/ml.
this is what I have come up with so far, but I am not sure if itis correct, and am not sure how to use it to determine how muchabsorbance is from protein or nucleic acid.
A280=Cprotein280*εprotein280 +Cnucleicacid280*εnucleic acid280
andA260=Cprotein260*εprotein260 +Cnucleic acid260*εnucleic acid260
A280=(0.58mg/ml)*(0.894cm-1M-1) + (0.04mg/ml)*(10.8cm-1M-1)
A280=0.51852+0.432
A280=0.95052
and A260=(0.58mg/ml)(0.512cm-1M-1) + (0.04 mg/ml)*(22.1cm-1M-1)
A260=0.29696+0.884
A260=1.18
