1. For a 1l10 dilution , pipette 100 L of unknown protein solution into clean cuvette ; add 900 L distilled water and invert to mix. For a 1/20 dilution, add 50 l of unknown protein solution + 950 L distilled water. For a 1/100 dilution, add 10 L of unknown protein solution + 990 L distilled water. Using these three dilutions, continue with the following instructions:
2. Add 1 mL of protein Dye Solution to the 1 mL of diluted protein. Make a Blank by mixing 1 mL of Protein Dye Solution with 1 mL of distilled water. At this point you should have blank and 3 Solutions of unknown protein concentration.
3. Determine the A620 of all three unknown protein solution.
4. If any of the absorbance fall off of the range of your protine standard curve, then the absorbance reading is invalid. If all of your absorbance fall off the range of your protein standard curve then you should repeat the measurement using the greater dilution of unknown protine solution.
5. If the absorbance reading is in the linear range of the curve, and above the lowest detectable amount, record this value and use it to determine the protein concentration of that fraction.
6. Using the BSA standard curve, determine the protein concentration of each fraction in
7. When finished, rinse all tubes thoroughly in warm running tap water and then submerse them ia pan of water for later washing.
8. Cuvettes should be carefully rinsed with warm running tab water and the inside surfaces of the Cuvettes should be gently rubbed with wet cotton swabs to remove any adherent Coomassie stain. The Cuvettes should be rinsed one final time in RO water and turned upside down to dry on a piece of absorbent material or paper towel.