How can the protein be eluted?
Elution is performed by the addition of 2.5 mM desthiobiotin, a derivative of biotin. It is a stable, reversibly binding (columns can be regenerated) low molecular weight substance which does not interfere with the protein or general protein assays. • Is the protein’s bioactivity preserved? Yes. Bioactivity is preserved due to the mild washing and elution conditions by the use of physiological buffers. • When the protein elutes from the column, is it complexed with desthiobiotin? No. Desthiobiotin can be removed via gel filtration or dialysis • Is the Strep-tag® system stable in the presence of imidazole? Yes, the Strep-tag system tolerates up to 250 mM imidazole in the protein extract. Therefore, elution fractions from Ni-NTA resins can be directly applied on Strep-Tactin columns, which is very useful in double-tag purification protocols.
