I have stock solution of 5% BSA prepared in TBST I use to make primary antibody dilutions for western blot. I'll admit I just assumed -20C, with freezing and thawing as needed, was an acceptable means of storage, but I've found online that people recommend just 4C. Would -20 and freezing harm the potency of BSA? I haven't observed precipitate so I haven't assumed so, but perhaps there are other consequences..

  • $\begingroup$ The question is, if freezing is necessary. I usually made small batches and kept them in the fridge. I also made sure to not store them too long to avoid contamination. $\endgroup$
    – Chris
    Dec 20, 2023 at 17:37
  • $\begingroup$ Have you had anomalous or unexpected results from your Western blots? If you do positive controls and negative controls and they are well-behaved, then I would infer that freezing the blocking agent has not been detrimental. If the blocking agent is not doing it's intended job, then I would predict higher or unacceptable background on a Western. You can use many different non-specific proteins, e.g., casein, gelatin, in addition to BSA. $\endgroup$
    – mdperry
    Dec 24, 2023 at 17:30


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