I have two static (structural modifications):
- The N-terminus of the peptide is modified by phenylisocyanite.
- The NH2 group of Lys is modified by propionyl group.
it so happens that I have a peptide that has K on the N-terminus:
KQLATKAAR
meaning the first Lys should have both phenylisocyanite and propionyl
how ever when loading the peptide in skyline only adds propionyl, ignoring phenylisocyanite
if I however add Ala to the peptide N terminus
AKQLATKAAR
I do get A modified with phenylisocyanite and Lys with propionyl.
How do I force skyline to add both structural modifications to K in KQLATKAAR?