Propionylation of lysine residues (Kpr) has recently become an important reversible PTM in mammalian cells. It was found that BCAAs dose-dependently increased protein propionylation in human platelets. Compared with wild-type platelets, the level of protein propionylation in PP2Cm-/- platelets is reduced. The results of immunoprecipitation and mass spectrometry showed that most propionylated proteins are cytoskeletal proteins, such as tropomodulin-3(TMOD3), PDM1L1, etc. Among them, only TMOD3 propionylation in human platelets showed a BCAA dose-dependent pattern. Therefore, TMOD3 propionylation is involved in αIIbβ3-mediated platelet activation.