Which of the following preparations is essentially a pure pr

Which of the following preparations is essentially a pure protein?

Proteins present in the serum-free culture medium of a cell

Cytoplasmic soluble proteins

Proteins secreted by a cell

Nuclear proteins

None of these

Solution

Cytoplasmic soluble proteins

To purify a pure protein fractionate the cell into components and determine which component is enriched in the protein of interest. the fractionation yielding a dense pellet of heavy material at the bottom of the centrifuge tube and a lighter supernatant above. the supernatent is cytoplasmic soluble proteins that can be paas through a affinity purification column and we can get a pure protein.