We aimed at identify variants of the mitochondrial Cyclophilin D from total lysates of human skin fibroblasts and murine tissues. Total lysates were loaded onto SDS-PAGE stained with MS-compatible Coomassie and bands around 19 and 18 kDa were manually excised. In fact in Western blots analysis of CyPD, which is the sole known mitochondrial Cyclophilin, often show two distinct bands at that molecular weights.