What is the minimum amount of papain (23500 Da) that I can see in the SDS PAGE gel?

I am performing reaction between iodoacetyl-PEG-biotin (linker) and papain. Thiol group of papain reacts with the linker to form a thioester bond. then I use streptavidin beads to fish out papain...

29 December 2015 4,901 3 View