Investigation of some covalent and noncovalent complexes by matrix-assisted laser desorption/ionization time-of-flight and electrospray mass spectrometry

✍ Scribed by Ellenia Bordini; Mahmoud Hamdan

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 138 KB
• Volume: 13
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/(sici)1097-0231(19990630)13:12<1143::aid-rcm626>3.0.co;2-j

✦ Synopsis

Covalent and noncovalent complexes involving bovine superoxide dismutase, bovine a-lactalbumin and two variants, A and B, of bovine b-lactoglobulin have been examined by delayed extraction matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and electrospray mass spectrometry. Covalent complexation with acrylamide was obtained through the interaction of these proteins with acrylamide monomers while treatment with peroxynitrite yielded complexes with NO 2 . Some of the complexation sites with acrylamide were reliably identified by performing tryptic digestion followed by MALDI-TOF measurements in the reflectron mode. These data demonstrate that the presence of free cysteine in the investigated sequences is not a precondition for the observation of Cys-acrylamide complexes. Although the bulk of the present work is dedicated to the characterization of Cys-acrylamide adducts, the preliminary data on noncovalent complexes between two of those proteins and 8-anilinonaphthalene-1-sulfonic acid (ANS) were easily observed under electrospray conditions, while under MALDI-TOF conditions only the complex with b-lactoglobulin B was clearly evident. The presented data demonstrate the advantage of the parallel use of both ionization techniques for this type of investigation.