You have prepared a protein extract from a tissue, and before running an SDS polyacrylamide gel, you need to determine the protein concentration in the extract, so you know what volume of extract you need to load on the gel to give 15 μg total protein. You dilute 10 uL of the protein extract with 90 uL of buffer and measure the protein concentration. The measured absorbance is 1.20. Using the diluted protein extract, you further dilute by 4 fold. From the standard curve, you get an absorbance reading of 0.3. What was the protein concentration in the undiluted protein extract in mg/ml?
Explain which equation to use to solve this and how it is worked out?