Hi Mintu, I suggest using purified whole protein for ESI-MS. You will get a series of protein peaks (if the substitution is not 100%, which is often the case), each differ for 47 Dalton. You can determine how many Se each peak corresponds to if you know the molecular weight of your protein. Then you can integrate the peaks to get an overall incorporation percentage.
Zhijie From: Mintu Chandra Sent: Monday, June 23, 2014 11:57 PM To: [email protected] Subject: [ccp4bb] protocol for seleno-methionine incorporation... Dear all, Is there any standard protocol to know the number of incorporated seleno-methionine in a protein ??? I am growing one of the protein in minimal media for phase determination. I am using mass spectrometry facility to know the incorporated seleno-methionine but I wanted to know whether I should use the purified protein or digested protein for mass spectrometry. Thanks, Mintu Chandra. -- Mintu Chandra Senior Research Fellow IISER BHOPAL [email protected] +918085288853
