Question

David, an undergraduate student in our lab, finally purified a protein of interest. He elute his protein using a 0.5M Imidazole in 1X TBS buffer. But, imidazole is destroying his enzyme assays in the next step. Please help him to solve this problem.

Answer 1

In order to solve this problem,

The elution step of protein using 0.5 M imidazole in 1X TBS causes the addition of more salt which results into protein precipitations.Therefore, imidazole in the protein elute destroys his enzyme assays. To avoid this condition, he should remove the imidazole from protein elute in next step ,that can be done by the dialysis ,Ammonium sulfate precipitation of protein,ultracentrifugation or by the helps of size exclusion desalting column.