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Analysis of effect of casein phosphopeptides on zinc binding using mass spectrometry
Author(s) -
Wang Jiaxi,
Green Kirk,
McGibbon Graham,
McCarry Brian
Publication year - 2007
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.2992
Subject(s) - chemistry , phosphopeptide , peptide , phosphorylation , mass spectrometry , electrospray ionization , zinc , protein mass spectrometry , chromatography , casein , electrospray , fragmentation (computing) , biochemistry , biophysics , organic chemistry , computer science , biology , operating system
Phosphorylation is one of the key events in signal transduction and zinc plays an important catalytic and/or structural role in many biological systems. The binding of Zn to a phosphopeptide will alter the physiological functions of a peptide. The binding of casein phosphopeptides (CPPs) to Zn has been analyzed using nanospray mass spectrometry. Electrospray ionization (ESI) spectra of peptides produced by tryptic digestion of α ‐casein incubated with Zn show both free and Zn‐bound phosphopeptides. The interaction of CPPs and the corresponding dephosphorylated peptides with zinc is compared. This study demonstrates that the phosphorylation state of a peptide dramatically affects Zn binding, with the decrease in Zn‐bound forms of peptide paralleling the decrease in phosphorylation as casein is chemically dephosphorylated, although, in some cases, a small amount of residual Zn‐binding capacity remains in the completely dephosphorylated peptide. The observed fragmentation patterns of the Zn‐bound CPPs support the thesis that nonphosphorylated residues are involved in the metal binding. Copyright © 2007 John Wiley & Sons, Ltd.