Removing MBP tag

[JackBean]

if is your protein in inclusion bodies, you express it in E. coli, right? What about trying yeast or something else?
If you have problems with inclusion bodies and want to keep E.coli, I suggest decreasing incubation temperature to ~25°C and using osmotic compounds as betaine. I have used it for my protein, which I couldn't get any activity before and then it was fine.