Effective Enrichment and Mass Spectrometry Analysis of Phosphopeptides Using Mesoporous Metal Oxide Nanomaterials

摘要

Mass spectrometry (MS)-based phosphoproteomics remains challenging due to the low abundance of phosphoproteins and substoichiometric phosphorylation. This demands better methods to effectively enrich phosphoproteins/peptides prior to MS analysis. We have previously communicated the first use of mesoporous zirconium dioxide (ZrO_(2)) nanomaterials for effective phosphopeptide enrichment. Here, we present the full report including the synthesis, characterization, and application of mesoporous titanium dioxide (TiO_(2)), ZrO_(2), and hafnium dioxide (HfO_(2)) in phosphopeptide enrichment and MS analysis. Mesoporous ZrO_(2) and HfO_(2) are demonstrated to be superior to TiO_(2) for phosphopeptide enrichment from a complex mixture with high specificity (>99percent), which could almost be considered as a "purification", mainly because of the extremely large active surface area of mesoporous nanomaterials. A single enrichment and Fourier transform MS analysis of phosphopeptides digested from a complex mixture containing 7percent of alpha-casein identified 21 out of 22 phosphorylation sites for alpha-casein. Moreover, the mesoporous ZrO_(2) and HfO_(2) can be reused after a simple solution regeneration procedure with comparable enrichment performance to that of fresh materials. Mesoporous ZrO_(2) and HfO_(2) nanomaterials hold great promise for applications in MS-based phosphoproteomics.