Currently, as a beginner, I'm performing solubility analysis (with UV based spectrometry) for practices. The protein I'm using now is BSA. This is widely used and cheap option.

I'm now looking for a cheap negative control protein which I can use to compare with BSA. It has to be much less soluble than BSA.

What are the good choice of proteins for that?

  • 1
    $\begingroup$ Protein solubility is not a simple concept. For instance proteins are colloidal and may aggregate to form a new highly hydrated phase that may slowly form and precipitate. One way to encourage aggregation is to use a buffer at the pI of the protein, so you may be able to do this with BSA. $\endgroup$
    – Buck Thorn
    Commented Jun 1, 2022 at 12:59
  • $\begingroup$ @BuckThorn Thanks so much. Can you advice the simple protocol to go about it? What type of buffer, how much etc. $\endgroup$ Commented Jun 2, 2022 at 0:09
  • $\begingroup$ @BuckThorn and with your method, how can we calculate the molecular weight of the new protein we create? $\endgroup$ Commented Jun 2, 2022 at 7:53
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    $\begingroup$ One technique to determine oligomerization state and distribution is size exclusion chromatography. Whether this is the right technique depends somewhat on the size and stability of the protein aggregates. $\endgroup$
    – Buck Thorn
    Commented Jun 2, 2022 at 9:24
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    $\begingroup$ Can you explain how you would use an insoluble protein as a negative control? Is it just a precipitate at the bottom of the cuvette? And why is that a negative control rather than just zero protein as the negative control? $\endgroup$
    – Andrew
    Commented Jun 3, 2022 at 14:04


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