Peroxisomal sarcosine oxidase (PIPOX aka L-pipecolate oxidase) is an important enzyme in the pipecolate pathway of lysine degradation. The saccharopine pathway is the predominant lysine degradative pathway in extracerebral tissues, whereas the pipecolate pathway predominates in adult brain. PIPOX can mediate the oxidation of L-pipecolate (PPCA) to (S)-1-piperideine-6-carboxylate (P6C), an intermediate in equilibrium with alpha-aminoadipate delta-semialdehyde (AAS), which connects the two degradative pathways. Patients lacking PIPOX accumulate PPCA which can lead to psychiatric and neurological disorders (Dodt et al. 2000, Hallen et al. 2013).