ornithine (cytosolic) + citrulline (mitochondrial) => ornithine (mitochondrial) + citrulline (cytosolic) Authored: D'Eustachio, P, 2003-06-24 00:00:00 Edited: D'Eustachio, P, 2003-06-24 00:00:00 Pubmed10369256 Pubmed12807890 Pubmed12948741 Reactome Database ID Release 4370634 Reactome, http://www.reactome.org ReactomeREACT_151 The mitochondrial ornithine transporters SLC25A15 and SLC25A2 mediate the exchange of cytosolic ornithine for citrulline from the mitochondrial matrix. SLC25A15 was the first protein shown to have this function, identified because mutations in the protein are associated with elevated levels of ammonia, ornithine, and citrulline in affected individuals (Camacho et al. 1999). The second transporter, SLC25A2, identified later, is also expressed in normal cells and their apparently partly redundant function may explain the relatively mild symptoms associated with SLC25A15 deficiency compared to other defects of the urea cycle (Fiermonte et al. 2003).