Physical properties and chemical compositions of cytoplasmic and mitochondrial malate dehydrogenase from Physarum polycephalum.

The malate dehydrogenase isoenzymes from Physarum polycephalum have been purified to homogeneity as confirmed by gel filtration chromatography, polyacrylamide gel disc electrophoresis and analytical ultracentrifugation. Certain physical and chemical parameters of the malate dehydrogenase isoenzymes reported here include sedimentation, molecular weight and subunit molecular weight. Most unique of the differences between the isoenzymes were the widely separate isoelectric points of 9.83 for mitochondrial malate dehydrogenase and 6.14 for the supernatant malate dehydrogenase. The amino acid analyses of each form were done revealing the isoenzymes were unquestionably unique proteins differing in the content of ten amino acids.