Enter your raw data for the absorbance measurements of the samples from the bovine serum albumi (BSA) standard curve
1. Calculate the average absorbance value for each of the duplicate samples
2. Then determine the total amount of protein in each of the pairs of tubes. Remember that the stock solution is 1.0 mg/mL or 1.0 ttg/pL. Example: if tube 2 contains 5 ttL of solution you would conclude that it also contains 5 pig of protein since it contains 1.0 gg/pL of BSA.
3. Using a piece of linear graph paper, plot the average absorbance values as a function of the amount of BSA in each pair of tubes. Draw a "best fit" straight line through data points with a ruler. This line should go through the origin since 0 BSA = 0 Absorbance. The line should pass through or come close to most of the data points. You might find, however, that the standard curve becomes nonlinear at high protein concentrations. (Insert a copy of this graph into your lab manual after this page) Note: non-linearity is not slight deviations; instead it is the beginning of a slight curve and should not appear in these data since you are using fairly small concentrations.
4. Discuss the graph with the instructor. If it looks good, you can proceed to the next part of the experiment. If some of the points deviate badly from the straight line, set up new tubes for those amounts of protein and repeat the assay.
5. Once you get a good standard curve, make up a conversion factor relating the absorbance at 595 nm to the amount of protein ( A59,5/µg). This conversion factor is the slope of the line through the linear region of the standard curve and can be calculated from any convenient set of points within the linear region. Record your conversion factor in your lab notebook.