Reversible Inactivation of Citrate Lyase: Effect of Metal Ions and Adenine Nucleotides

Abstract
The inactivation of citrate oxaloacetate‐lyase in dilute solution is complex, at least two processes occurring, one reversible and the other irreversible. Inactivation at low magnesium concentration (0.025–0.1 mM) and reactivation at higher magnesium concentration (2.5 mM) have been investigated. The adenine nucleotides and EDTA exert effects related to the stability constants of their complexes with magnesium. Although unable to activate citrate lyase, Ca2+can protect the enzyme from inactivation in dilute solution.