Polymeric forms of yeast nicotinamide-adenine dinucleotide-specific isocitrate dehydrogenase in the presence of various ligands.
The molecular weight of NAD-specific isocitrate dehydrogenase, purified from baker's yeast, has been studied by molecular sieve chromatography. By elution of the enzyme from columns of Sepharose 6B with 0.05 M phosphate buffer, pH 7.6, a mol. wt of 151,000 was measured. Higher values of the mol. wt were measured in presence of the following ligands (mol. wt in parentheses): the substrate, isocitrate (224,000); the activators, citrate (203,000) and AMP (275,000); the inhibitor, NaCl (360,000). A mol. wt of 337,000 was measured when AMP, which antagonizes the inhibition by chloride, was present together with NaCl. The results indicate the absence of a correlation between the aggregation form of the enzyme in presence of the ligands and the effects of these ligands on the enzyme activity.
D000249:Adenosine Monophosphate; D002850:Chromatography, Gel / Q000379:methods; D002951:Citrates; D007521:Isocitrate Dehydrogenase / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D009243:NAD; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D012965:Sodium Chloride
D002951:Citrates; D046911:Macromolecular Substances; D009243:NAD; D000249:Adenosine Monophosphate; D012965:Sodium Chloride; D007521:Isocitrate Dehydrogenase