In order to evaluate the impact of PCYOX1 deletion on cardiomyocytes, we applied a label-free mass spectrometry-based proteomic approach to compare the proteome of mitochondria from Hl-1 after PCYOX1 gene silencing. Pcyox1 was silenced using shRNA lentiviral particles. Control cells were treated with shRNA lentiviral particles containing a negative construct.