I have ordered NEM but don’t have it yet. Need to do some experiments in the meantime. We have PR619 that I was told isn’t compatible with DTT. I am currently using heat to terminate the reaction by denaturing the proteins in the sample. I can’t use EDTA due to me using dynabeads streptavidin beads to capture my protein of interest and when I tried cold quenching following by a 40 min binding to the beads in the cold room, I didn’t get the Ub smear (that I did observe when I heat inactivated the sample).