Nuclear glutamate dehydrogenase: unique antigenic determinants and determinants common to the mitochondrial enzyme

An antiserum against glutamate dehydrogenase from ox liver nuclei precipitates both the nuclear and the mitochondrial enzymes, with different equivalence zones. The antibodies of this serum have been fractionated by means of an immunoadsorbent to which mitochondrial glutamate dehydrogenase is covalently linked. After the affinity chromatography, the unretained antibodies had virtually lost the ability to precipitate the mitochondrial enzyme, whereas the retained portion, after elution, precipitated both glutamate dehydrogenases. These findings suggest that nuclear glutamate dehydrogenase contains specific antigenic determinants as well as determinants common to the mitochondrial enzyme, and that only the antibodies against the latter determinants have been selectively removed by the affinity chromatography.