4.2.1.2 Ca2+ has a small stimulatory effect 715093 4.2.1.2 Fe enzyme contains an oxygen-sensitive [4Fe-4S] cluster 679910 4.2.1.2 Fe2+ aerobic purification results in inactive protein, which can only partly be reactivated with Fe2+ and thiol 749072 4.2.1.2 Fe2+ storage of the protein for 6 months leads to almost complete loss of its activity, which can be fully restored by the reactivation with Fe2+ and thiol 746828 4.2.1.2 Iron fumarase A contains a catalytically active [4Fe-4S]cluster 33770 4.2.1.2 Iron in cells grown without aeration the Fe-S-independent enzyme form occupies over 80% of the overall fumarase. In aerobically grown cells the Fe-S-dependent fumarase occupies 80% of the overall activity 33747 4.2.1.2 Iron one Fe-S-dependent enzyme form and one Fe-S-independent enzyme form 33747, 33768 4.2.1.2 Iron [4Fe-4S]-cluster containing heterodimeric enzyme 745719 4.2.1.2 Mg2+ 10fold activation of isoform Fum2 749006 4.2.1.2 Mg2+ 2 mM, slight stimulation 678771