Are the buffers bought from a company and is there SDS inside? One PhD in our Lab changed the whole Kit because she was not able to read. How stuipid, isnt? Generally, most buffer are store in RT. If there is contamination then it is quite a old solution. Try to for cell culture always aotuclaving the solution and the others in the Lab as you know wiht ddH2O and store tightly closed. Make new once if frequently used. To my knowledge like TAE or TBE or Running Buffer you can make stock solutions so there is no chance to growth for contaminants. And its not specific for TRIS its just a matter of handling your solution. If i was able to help you.
as almost says, we need more detail and specification of your problem. But it seems that you just have different amount of actin as a internal control. Thats because your loading conc. are different when you perform SDS-PAGE.You can calculate the amount maybe with densitometric methods.
İ have a stupid question. İf i clone a HİS tag directly to my rProtein İ have no Amino Acid inbetween. But in case of GST Tag İ am getting additionally AA to my rProtein. Am İ right? How can İ avoid this.