I am trying to fragment a protein for peptide mapping (ie
N-terminal sequencing and Mass Spec), BUT the protein will not fragment.
I am using trypsin, chymotrypsin, elastase and V8 protease. There are
disulphide binds, but I have added 14mM mercaptoethanol. My question is:
what are my options for more vigourous attempts at fragmenting the
protein? Am I failing (for some reason) to break up the disulphides?
Thanks in advance for your opinions. Mike.