Protein Precipitation

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    • #10268
      Elinor
      Participant

      Hi everyone,
      I recently did a lab on protein precipitation and we used various reagents to precipitate the proteins from a standard protein solution. When I added copper sulphate solution and lead acetate solution, I got a white precipitate for both. I know that heavy metal ions are supposed to precipitate proteins out of solution but I can’t seem to find the theory behind it. Does anyone know how these ions precipitate proteins?……thanks

    • #86486
      mith
      Participant

      folding changes probably

    • #86490
      MichaelXY
      Participant

      CuSO4 + OH makes a copper Hydroxide which is a precipitate.

    • #86495
      blcr11
      Participant

      Things like Cu, Pb, and Hg bind strongly to the sulfurs of cysteines. They can sometimes bind to Histidines or the sidechains of Aspartates and Glutamates. They will sometimes displace structurally important metals, but the heavy metals are large (relative to things like Na or K or even Zn) and often dislocate parts of the protein molecule. Eventually, it can lead to denaturation and precipitation.

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