(Solved): You guess that the KDI will be secreted outside of the cell (so that it can work on the keratin out ...

You guess that the KDI will be secreted outside of the cell (so that it can work on the keratin outside), so you grow up P. decapillus, spin down the cells, and start with the medium in which the cells had grown. One of the disadvantages of this is the large volume of culture medium. It is too large to put down a chromatography column, so you decide to use ammonium sulfate precipitation to concentrate it. You add various amounts of $${\left({\mathrm{NH}}_4\right)}_2{\mathrm{SO}}_4$$, centrifuge the precipitated protein, remove the supernatant and then resuspend and dialyze the pellet against buffer to lower $$\left[{\left({\mathrm{NH}}_4\right)}_2{\mathrm{SO}}_4\right]$$ below $$0.1\%$$, as too much salt may inhibit the enzyme. You assay the dialysate (from the pellet). The results are shown in the table below: Based on this, what ammonium sulfate cut would you use, if you wanted to maximize both yield and purity? (e.9. A cut of $$50\%?70\%$$ means that you add ammonium sulfate to $$50\%$$, get rid of what precipitates, and then add more ammonium sulfate to $$70\%$$, and collect the precipitate, throwing away what remains soluble. In other words, you collect what is soluble at $$50\%$$ ammonium sulfate but insoluble at $$70\%$$ ammonium sulfate.) Your answer: a cut of