Investigation of Angiotensin Glycosylation by MALDI-TOF and ESI Tandem Mass Spectrometry

摘要

Angiotensin I,a model decapeptide,was glycosylated and partially hydrolyzed with HC1(6 N,80 deg C,4 h),aminopeptidase,and carboxypeptidase Y.A single peptide mass map obtained from truncated peptides in the partial acid hydrolysate of angiotensin and its glycosylation product mixture by matrix-assisted laser desorption/ionization time-of-flight(MALDI-TOF)mass spectrometry enabled sequencing of angiotensin by a combinatorial procedure.MALDI-TOF and electrospray ionization(ESI)tandem mass spectrometric results indicate that both the N-terminal amino group of aspartic acid and the guanidinium group of the second residue arginine are glycosylated.