Characterization of disulfide linkages and disulfide bond scrambling in recombinant human macrophage colony stimulating factor by fast-atom bombardment mass spectrometry of enzymatic digests

• Published in: Journal of the American Society for Mass Spectrometry Vol. 6; no. 8; pp. 638 - 643
• Main Authors: Glocker, M O, Arbogast, B, Deinzer, M L
• Format: Journal Article
• Language: English
• Published: United States 01.08.1995
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1016/1044-0305(95)00250-H

Fast-atom bombardment mass spectrometry was used to study disulfide bonding patterns in heat-denatured human recombinant macrophage colony stimulating factor (rhM-CSF). The heat-denaturated protein was studied by analysis of the pattern of peptides in the proteolytic digests. Native rhM-CSF is a homodimer with intramolecular disulfide linkages between Cys7-Cys90, Cys48-Cys139, and Cys102-Cys146 and intermolecular linkages between Cys31-Cys31, and the pairs Cys157 and Cys159. Brief heating for 1 min leads to partial disulfide bond scrambling. In addition to the native disulfide bonds between Cys7-Cys90, Cys48-Cys139, and Cys31-Cys31, nonnative disulfide bonds were detected between Cys48-Cys90 and Cys48-Cys102. When heated for 5 min the disulfide bonds of rhM-CSF are completely scrambled and lead to nonnative intramolecular disulfide bonds between Cys48-Cys102 and Cys90-Cys102 and one intermolecular disulfide bond between Cys102-Cys102.