You have a series of protein solutions of unknown concentration that you saved during your purification procedure. You prepare assay solutions using 50 uL from each of these samples, which yield the follow A595 values: Sample 1: Crude homogenate: 2.031
Sample 2: Metal ion affinity chromatography fraction: 0.640
Sample 3: G-25 buffer exchange fraction: 0.592

a. Which of these sample concentrations can be reliably determined using your standard curve?

1. 0.086=.0369x+.0495
x=.98915

2. 0.13=.0369x+.0495
x= 2.18157

3. 0.037=.0369x+.0495
x= -.33875

4. 0.009=.0369x+.0495
x=-1.09756

5. 0.011=.0369x+.0495
x=-1.04336

6. 0.008=.0369x+.0495
x=-1.12466

b. What is the protein concentration in these samples (in mg/mL)?
c. How would you measure protein concentrations for the sample(s) whose concentrations cannot be reliably determined from the values given?
d. Is the Bradford protein assay the best choice for this analysis? Why or why not?
e. Suppose the molecular weight of your protein of interest is 32,500 daltons. What is the molar concentration of protein in the final purified protein in the G-25 buffer exchange fraction?