Studies in neuronal ceroid lipofuscinosis: Enzymes of liver and brain tissues involved in the defense against oxidative damage

The levels and the nature of peroxidase isozymes in the liver and brain tissues of a patient with Batten‐Spielmeyer‐Vogts (BSV) syndrome were found to be comparable to those of normal controls, indicating that peroxidase deficiency is probably not the basic genetic defect in Battens disease. The isoelectric focusing profile (four isozymes at pI 4.0, 4.5, 5.3, and 7.2) of liver peroxidases in the BSV patient was similar to that of normal control. Ion exchange chromatography revealed no noticeable difference in the liver peroxidase isozymes of the normal control and the BSV syndrome patient. The quantitative difference often observed in total peroxidase activity in normals and BSV syndrome patients can be attributed to different amounts of hemoglobin, which is known to express peroxidase activity. The levels of other enzymes known to be involved in the defense of tissues against oxidative damage, such as superoxide dismutase and glutathione peroxidase, and catalatic and peroxidatic activities of catalalase in the liver and brain tissues of the Battens patient, were comparable to the levels in the control subject. The brain peroxidase from both normal subjects and the Battens patient was completely inhibited by 5 mM sodium azide, whereas it did not affect the liver peroxidase activity.