I want to express and purify HCN1 channel protein. Will I get a good protein expression if I transiently transfect HEK cells with my channel expressed in a plasmid? This is all very new to me and I am concerned about the purity of my protein which I'll get from my cell lysate. I'll be using it in further pull-down experiments, so how would I determine if it is HCN1 I have expressed and purified. I would need may be 1-2 mgs of protein for my experiments.