Hi all,
I have a protein supposed to be around 20 kDa, but somehow on SDS-PAGE it runs at 40 kDa and previous literature also showed the same behavior and suggested a dimer complex. I am little bit confused, since it is a denaturing gel (4-20% tricine gel). I have sent the protein solution for mass-spec as well as the protein band. I am wondering if mass-spec can tell the protein could form a covalent bonded dimer? If so, how do I obtain that information or do I need any special mass-spec?