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disulfide bonds in proteins - (Oct/09/2005 )

Hello friends,

I'm confused that if we cut down disulfide bonds (S-S).
Will the protein M.W. be corresponding to decrease?

Because what I thought was if I didn't cut peptide bonds, the protein M.W. should be still the same. I cut and modified on S-S bonds only.
Disulfide bonds are importantly to control the protein structure so I may just rearrange the
structure of protein, but not cut any fragments? Am I right?

Thank you in advance
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i think the proteins MW will be the same

you are not taking away anything but an interaction; the molecule will still be the same size just in a different shape


I don't think so.

If the disulfide bonds connect the same unit,that means the disulfide bonds is intramolecular,the mass of the protein should be still the same. But if the disulfide bonds is intermolecular,when you cut peptide bonds,the m.w will change.


if the disulfide bonds holds certain monomers together, then yes, you will get a lower molecular weight. in fact, you might see the monomers and their respective dimers, etc on the same gel. hence you will get the large molecule and its respective sub-units.


Hi all,
I have a question on stability of disulfide bond. I dissolved my target protein (three intermolecular disulfide bonds) into GnCl 6M/0.2M HCl. Is there any affect on the disulfide bonds? In addition, I used Cyanogen bromide (CNBr) to remove fusion partner from my authentic protein (1mg/ml) in the condition: 25oC, 16h in dark, 400mM CNBr; could CNBr modify my protein?