Title : Glycoproteomic characterization of
butyrylcholinesterase from human plasma
Abstract :
- Human butyrylcholinesterase ( hBChE ) is a highly glycosylated protein present in human plasma
- The enzyme hydrolyses choline esters, for example benzoylcholine, butyrylthiocholine and acetylthiocholine as well as noncholine esters like heroin and aspirin
- hBChE is primarily involved in neuronal transmission and is a potential bioscavenger of toxic organophosphates to protect acetylcholinesterase
- A prerequisite for the therapeutic use of hBChE is a detailed characterization of this glycoprotein purified from human plasma
- In this study, MS/MS could confirm most of the protein backbone, including the N- and the C-terminus
- Site-specific analysis of all nine potential N-glycosylation sites revealed mainly mono- and disialylated N-glycans to be present on this glycoprotein
- Sialic acids (Neu5Ac) are mainly alpha2,6-linked, however a fraction of the N-glycans contained Neu5Ac also in alpha2,3 linkage
- On monosialylated N-glycans, sialic acid is exclusively located on the 3-arm and in alpha2,6 linkage, as verified by 2D-HPLC and exoglycosidase digests of 2-aminopyridine (PA)-labelled N-glycans
- This first comprehensive glycoproteomic analysis of the important human plasma glycoprotein BChE did not give any indication of O-glycosylation or any other kind of PTMs as previously postulated