Figure 1.
Effect of an R9 tag on the purification of a protein by cation-exchange chromatography. (A) RNase A-R9 was purified by cation-exchange chromatography before (−CPB) and after (+CPB) the addition of carboxypeptidase B. (B) SDS-PAGE gel of RNase A-R9 before (−CPB) and after (+CPB) the addition of carboxypeptidase B. Purified RNase A is a standard.