Does anyone had an abundant impurity at the size of ~40 kDa while purifying His tag protein from Sf9 culture media on a HisTrap-FF column?

08 August 2016 1 9K Report

This impurity was observed only in the elution fractions (500 mM imidazole). There were no traces of it in the washes (20mM and 50 mM imidazole).

Gary S. Laco

have not, do you batch bind to the resin, wash, then pour into a column? What size is the His-tagged protein you over expressed? Also, the HisTrapp-FF columns are not the most selective, Talon is better, followed by Complete (Roche).

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