BCA Protein Assay Kit

Take the microplate reader detection method as an example:

1. Mix BCA Reagent A and BCA Reagent B in a ratio of 50:1. That is, mix 50 ml BCA Reagent A with 1 ml BCA Reagent B.

NOTE: Use the following formula to determine the total amount of working reagent required:

(Standard + sample to be tested) *(number of repetitions) * (BCA working solution required for each sample) = total volume of BCA working solution required.

2. Add 25μl of each standard and protein sample to separate microplate wells.

Note: If the protein sample is very precious, you can dilute the protein sample 5-10 times with PBS and multiply the dilution factor when calculating the protein concentration.

3. Add 200μl BCA working reagent to each well and mix.

4. Seal the plate and incubate at 37°C for 30 minutes.

5. Cool the plate to room temperature (RT).

6. Measure the absorbance at 562 nm on the plate reader within 10 minutes.

7. Subtract the OD562 of the blank from all readings and draw a BSA standard curve: OD562 (on the Y-axis) versus the BSA standard concentration (on the X-axis).

8. Use the standard curve to determine the protein concentration of each sample to be tested.

Important product information

1. If this kit is received or stored cold, a precipitate may form in Reagent A or Reagent B. To dissolve the precipitate, warm the solution slowly at 37°C while mixing or microwave for a few seconds. Discard the kit if it is contaminated by bacteria

2. If interference caused by reducing substances or metal- chelating substances contained in the sample remains, Bradford Assay Kit (GK10027) is recommended.

3. It is recommended that the standard of different concentrations and samples be assayed in duplicate. Standard curve should be plotted for each assay.

4. Newly formed green turbidity will disappear after mixing Reagent A and Reagent B thoroughly. It will not affect the performance.

5. Assayed sample amount will be reduced while using spectrophotometer to detect protein concentration. When using 37° C incubator, prevent the influence of water evaporation.

6. Several ways for eliminating or minimizing the effects of interfering substances:

• Remove interfering substances by dialysis or gel filtration.

• Dilute the sample until substances no longer interfere.

• Since detergents of high concentrations also affect the results, precipitate the proteins in the sample with trichloroacetic acid (TCA).

7.Avoid using substances including reducing substances, chelating agents, strong acid and alkali since they interfere with protein estimation even at very low concentration.