Updated project metadata. We present three different methods for protein extraction from fresh frozen mouse heart tissue: 1) extraction using SDS buffer followed by FASP purification, 2) extraction using SDS buffer followed by S-Trap purification, and 3) extraction using a guanidine hydrochloride buffer followed by in-solution digestion. Based on bicinchoninic acid assay, all three methods display similar recovery of total protein content. However, proteomics-based analysis identified far fewer proteins from the extraction guanidine hydrochloride. SDS-FASP identifies as many proteins as the SDS-STrap method with good coverage of proteins from different cellular compartments.