[shinjinee6]

Hi,

I am working with a methylated and non-methylated enzyme named trehalose-6-phosphate synthase (TPS). I want to find out the difference between the molecular weight of both methylated and non-methylated TPS. What I want to know is the various ways to find out the molecular weight difference including MALDI? The molecular weight of non methylated TPS will be around ~ 59 KD. Any ideas?

[Yggdrasil]

Detecting the change in molecular weight due to attachment of a methy group (15 Da per methyl group) requires a very sensitive technique, so mass spectrometry (either MALDI or other ionization technique like ESI) will be the way to go.  It may be helpful to first digest the protein with trypsin prior to performing the mass spec.  If you wish to figure out the amino acid residues to which the methyl groups are attached, using a technique like MS/MS that fragments the peptides and allows you to sequence them would be a good idea.

[shinjinee6]

Thanks for the reply. I will try to proceed the way you have suggested.