Updated FTP location. The mitochondrial preparations of cardiac tissue from mice treated with TMAO or PBS (control) were subjected to SDS-PAGE, followed by trypsin digestion for mass spectrometric analysis. SDS-PAGE gels were subjected to in-gel digestion with trypsin. Peptides generated from each sample were injected into a nano-flow liquid chromatograph coupled with a tandem mass spectrometer via a nano-ESI ion source.