An Overview of Mass Spectrometry-Based Methods to Analyze Post-Translational Modifications.

Post-translational modifications (PTM) are the covalent modifications of proteins after their biosynthesis. PTMs change the structure and functions of proteins, which eventually regulate various biological processes that are closely related to the onset and development of diseases. Hundreds of different forms of PTMs have been discovered so far and mass spectrometry (MS) has become one of the most important tools to analyze PTMs. With the development of new methods in sample preparation, advances in MS instrumentation, and inventions of new bioinformatic tools, MS-based methods can identify most forms of PTMs, precisely locate the site of modification, sensitively and accurately quantify the changes of modification levels from various of biological samples. This chapter will summarize generic procedures to analyze PTMs with MS methods and provide an update with the latest development in sample preparation, MS analysis, and database search that advanced the way for PTM analysis, improving our knowledge of PTMs and understanding of their roles in various diseases.