Identification of L-pipecolate oxidase in human liver and its deficiency in the Zellweger syndrome.

The ability of human liver to oxidize L-pipecolic acid was investigated. Liver from control subjects was found to contain L-pipecolic acid oxidase, an H2O2-producing enzyme not previously demonstrated in mammals. In livers from patients with the cerebro-hepato-renal syndrome of Zellweger, a genetic disease characterized by the absence of morphologically distinguishable peroxisomes, L-pipecolic acid oxidase was found to be deficient. These results indicate that L-pipecolic acid oxidase is a peroxisomal enzyme in man and provide an explanation for the fact that elevated levels of L-pipecolic acid are found in body fluids of patients with the Zellweger syndrome.