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Tryptic mapping of human chorionic gonadotropin by matrix‐assisted laser desorption/ionization mass spectrometry
Author(s) -
Laidler Paul,
Hider Robert C.,
Cowan David A.,
Kicman Andrew T.,
Keane Anita
Publication year - 1995
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1290091110
Subject(s) - chemistry , mass spectrometry , human chorionic gonadotropin , chromatography , protein mass spectrometry , peptide , matrix assisted laser desorption/ionization , ionization , ion , desorption , biochemistry , tandem mass spectrometry , organic chemistry , adsorption , hormone
Abstract The potential of matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI)(I‐TOF) mass spectrometry for use in the identification of human chorionic gonadotropin (hCG) seized by law enforcement agencies is investigated. Analysis of untreated hCG revealed signals corresponding to the molecular ions of the intact hCG heterodimer and both its non‐covalently linked subunits. Unfortunately, due to carbohydrate heterogeneity, the peaks are broad which makes accurate mass assignment, and consequently identification, difficult. Peptide mapping by MALDI‐TOF following‐tryptic digestion gave sequence coverage of 59% and 52% for the α and b̃‐subunits respectively. Nevertheless, the tryptic map was considered to provide unambiguous identification of hCG. This was confirmed by searching peptide‐mass databases with the experimentally determined masses. Our data suggest that peptide mapping by proteolytic digestion followed by MALDI‐TOF mass spectrometry is a suitable analytical technique for the identification of hCG seized by the legal authorities.