A study of the biochemical characteristics of NADP+ isocitrate dehydrogenase from the liver and kidney of the arabian camel (Camelus dromedarius)

Abstract 1. 1. NADP + isocitrate dehydrogenase was partially purified from camel liver and kidney by an FPLC. 2. 2. The specific activity of the purified preparation from liver was 63.5 μmol/min/mg protein and from the kidney was similar, 58.7 μmol/min/mg protein. 3. 3. The enzyme from the two sources were similar in their pH optimum (7.6), electrophoretic mobility and stability to thermal inactivation at 60°C. 4. 4. Heat inactivation was accelerated by oxidized glutathione and cystine and decreased by dithiothreitol, reduced glutathione and cysteine. 5. 5. The molecular weight of the enzyme from both organs was estimated as 60,000 ± 5000. 6. 6. Divalent metal ions increased the activities of both enzymes, with maximum catalytic activity in the presence of Mn 2+ ions.