While performing biotinylation at the N-terminal of the peptide, I observed that the most intense mass peak corresponds to the peak tat is 216 Da off than parent peak. Has anyone else encountered a similar result or have any insights on this?
Higher or lower than expected? What is the precision of the measurement (how much of a difference in mass could be within the error range of the measurement)?
Thank you so much for your response, Adam B. Shapiro. I really appreciate your help. I am getting 216 Da lower than the actual mass, which is quite puzzling. I’m using Fmoc-lysine biotin as my biotinylation reagent. Your insights would be invaluable as I try to figure this out.