Functional human kinases
isolated and purified from HEK-293 cells
using the HaloTag platform. (A) Five human kinases were selected for
isolation and purification. (B) To compare the efficiency of HaloTag
to that of other protein tagging systems, PKCγ and PI3Kγ
were transiently expressed in HEK-293 cells using four protein labeling
protocols, including HaloTag, FLAG, 3× FLAG, and His-Tag. Purified
proteins were analyzed by SDS-PAGE. Each protein tagging method resulted
in purified protein, yet only HaloTag displayed a single band. The
arrow denotes the expected molecular weight of the protein. (C) Protein
recovery was determined using normalized volumes of soluble lysate
(S), unbound fractions (FT), and purified protein (Y) with the addition
of a protease using SDS-PAGE and western blot analysis. (D) The HaloTag
platform provided the highest purity of protein for both kinases,
as compared to that with the other systems. The percent recovery was
also shown to be much higher for the HaloTag system. Reprinted with
permission from ref (20). Copyright 2011 Elsevier.