A glutamyl residue in the active site of triphosphopyridine nucleotide-dependent isocitrate dehydrogenase of pig heart.

Kinetic evidence for the dimerization of the triphosphopyridine nucleotide-dependent isocitrate dehydrogenase from pig heart.

Role of metal ions in reactions catalyzed by pig heart triphosphopyridine nucleotide-dependent isocitrate dehydrogenase. II. Effect on catalytic properties and reactivity of amino acid residues.

The TPN-specific isocitrate dehydrogenase of pig heart, which is here shown not to contain zinc or manganese as essential constituents, is most effectively activated by divalent manganous ions. On the basis of the effect of isocitrate concentration on the apparent Michaelis constant for manganous ion and the reciprocal influence of manganous ion concentration on the apparent Michaelis constant ...

Binding of ligands to half of subunits of NAD-dependent isocitrate dehydrogenase from pig heart. Binding of manganous ion, isocitrate, ADP and NAD.

NAD-dependent isocitrate dehydrogenase from pig heart contains three types of subunits of slightly different molecular weights in an approximate ratio of 2:l:l. Ultrafiltration binding experiments at pH 6.1 indicate 1 binding site for every 2 subunits for several different ligands. The metal activator, Mn2+, binds to isocitrate dehydrogenase in the absence of other ligands ( K D = 115 p ~ ) . M...

Triphosphopyridine nucleotide linked isocitric dehydrogenase in bacteria.

The conversion of isocitric acid to alpha-ketoglutarate has been demonstrated both in animal tissues (Martius, 1937; Krebs and Johnson, 1937; Adler et al., 1939; Ochoa, 1948) and in yeast (Kornberg and Pricer, 1951; Foulkes, 1951). Triphosphopyridine nucleotide was first implicated as a specific coenzyme for this reaction by Adler et al. (1939). Recently Kornberg and Pricer (1951) found in yeas...

Identification of metal-isocitrate binding site of pig heart NADP-specific isocitrate dehydrogenase by affinity cleavage of the enzyme by Fe(2+)-isocitrate.

The divalent metal-isocitrate site of pig heart NADP-specific isocitrate dehydrogenase can be located by affinity cleavage of the enzyme by Fe(2+)-isocitrate in the presence of O2, in analogy to the "chemical nuclease" action of DNA-binding drugs linked to Fe-EDTA. The enzyme is irreversibly inactivated and cleaved by Fe(2+)-isocitrate more rapidly than by Fe2+. Mn2+ prevents inactivation and c...