Question:

We have previously purchased batches of your EBV-protein enriched B cell lysate (cat. no. EV012). We have some specific questions on the lysates:

  1. Why are the lysates dissolved in a glycine buffer at pH 9,5? Is it to avoid proteolysis?
  2. Have you added any protease-inhibitors in your glycine buffer?
  3. We need to use the lysates at physiological pH 7.4. Could you please give us some advice on how to lower the pH without destroying the viral proteins? Should we dialyze the lysates or just lower the pH with acid?
  4. What buffer would you recommend that we use at pH 7,4?

Resolution:

  1. The glycine buffer at pH 9.5 is used to maximise protein solubility
  2. No protease inhibitors are used since the product is stored at -70°C
  3. Adjusting pH - for tissue culture experiments, dilution, dialysis or G-25 buffer exchange (PBS) is recommended since the glycine can be toxic to the cells. If the glycine is not a problem, just add sufficient 1M Phosphate (monobasic) to reduce the pH to the desired level. You can make some 100 mM Glycine pH 9.5 and determine how much 1M Phosphate will be needed to reduce the pH. This way you can avoid experimenting on your purchased antigen.
  4. PBS is usually the best general purpose buffer.