Comparative partial purification of the active dicarboxylate transport system of rat liver, kidney and heart mitochondria.

Hydroxylapatite chromatography of Triton-extracted inner-membrane proteins from rat liver mitochondria allowed a ten-fold purification of the dicarboxylate carrier. The purified system, reconstituted into liposomes, displayed all the properties of the dicarboxylate carrier and mediated malonate-malate and malonate-phosphate exchanges. Six protein bands of Mr ranging from 27,000 to 34,000 could be resolved by sodium dodecylsulfate-polyacrylamide gel electrophoresis. The purification of the dicarboxylate carriers of liver, kidney and heart mitochondria were carried out by this method and their properties were compared with respect to transport activity and electrophoresis patterns. Our results demonstrate that the dicarboxylate carrier of rat mitochondria can be obtained in an advanced state of purification and with a high specific activity.