Hi,
i checked the protein molecular wight by MS, the result is shown higher molecular wight (~1010 Da) than the theoretical one. The protein in 60mM HEPES contains (50 ug/ml peg20000, 3mM MnCl2, 3mM MgCl2, 3uM Na-orthovanadate, 1.2 DTT ). I checked the plsamid sequencing and it was right.
what happens to the protein MW, could it binds to something from the buffer reagent? .