Electrospray ionization mass spectrometry was used for the determination of calcium-binding stoichiometry for calcium-binding proteins. Bovine calmodulin, bovine α-lactalbumin, and rabbit parvalbumin were found to bind specifically to 4, 1, and 2 Ca2+ ions, respectively, in agreement with previously reported results obtained by using other physical methods. This mass spectrometry method could also be applied to proteins that bind more than one type of metal ion. The Zn2+- and Ca2+-binding stoichiometries for human stromelysin catalytic domain were determined to be 3 and 2, respectively.
ASJC Scopus subject areas
- Analytical Chemistry