Mitochondrial malate dehydrogenase and its precursor have different conformations

Antiserum prepared against the denatured form of mammalian malate dehydrogenase was found to immunoprecipitate the denatured but not the native form of the mature enzyme. In contrast, the antiserum immunoprecipitated the enzyme's precursor, synthesized in a rabbit reticulocyte lysate, either before or after denaturation. The mature form of the enzyme but not the precursor bound to an affinity column of 5'-AMP-Sepharose. These results indicate that the mature and precursor forms of malate dehydrogenase have different conformations.