Question

You are working in a clinical laboratory, as an entry-level laboratory technician (average salary $35k-$58k/yr). You have purified a novel anti-viral (a cyclic peptide!) with a molecular weight of 2 kDa using ammonia sulfate precipitation. Describe how you would separate the ammonia sulfate from your novel anti-viral using dialysis. It may be helpful to draw a flowchart

Answer 1

Answer-

According to the given question-

Ammonium sulfate precipitation- It is used for purification of proteins by changing the solubility of protein. Ammonium sulfate have high solubility with high ionic strength due to which the protein easily precipitated from the solution and the precipitated protein was recovered by centrifugation and transfered in fresh buffer.

After that the Ammonium sulfate was removed from the desired protein with the help of dialysis. here the size of dialysis membrane is depend upon the size of purified protein. here in given question we have 2 KDa and we have to separate the ammonia sulfate from your novel anti-viral cyclic peptide using dialysis so we have to choose the pore size of dialysis bag which size is less than 2KDa.

Dialysis- seperation based on the according to the size of protein. In this the coccentrated solution of protein along with ammonium sulphate are placed in the dilysis bag and placed in the buffer.

Due to which the solute whose size is less than the size of dialysis membrane moved out from the dialysis bag to the solution while the larger molecule or our desired protein remained in the dialysis bag . so by this method we can easily separate our desired novel peptide from the ammonium sulphate.