3.6.1.28 Zn2+ 0.01-0.05 mM at pH 8.0 activates GST-tagged thiamine triphosphatase by about 30% in the presence of Mg2+ 667797 3.6.1.28 Mn2+ 0.1 mM 667797 3.6.1.28 Ca2+ 12.7% of the activation with Mg2+ 210020 3.6.1.28 Mn2+ 30% of the activation with Mg2+ 210020 3.6.1.28 Ni2+ 30% of the activation with Mg2+ 210020 3.6.1.28 Zn2+ 30% of the activation with Mg2+ 210020 3.6.1.28 Mg2+ 5 mM, in the absence of Mg2+ the activity is still 40-50% of the maximum 667797 3.6.1.28 Ba2+ 7.3% of the activation with Mg2+ 210020 3.6.1.28 Mg2+ absolute requirement for divalent cations, Mg2+ is most effective 210020 3.6.1.28 Mg2+ activates 210024 3.6.1.28 Ca2+ activates membrane-associated enzyme 210016 3.6.1.28 Ca2+ divalent cation requirement is fullfilled by Mg2+ or Ca2+ in microsomes and by Mg2+ but not Ca2+ in soluble fraction 210010 3.6.1.28 Mg2+ divalent cation requirement is fullfilled by Mg2+ or Ca2+ in microsomes and by Mg2+ but not Ca2+ in soluble fraction 210010 3.6.1.28 Ca2+ divalent cation requirement is satisfied by Mg2+ or Ca2+ 210015 3.6.1.28 Mg2+ divalent cation requirement is satisfied by Mg2+ or Ca2+ 210015 3.6.1.28 Ca2+ divalent cation requirement is satisfied by Mg2+, Mn2+ or Ca2+ 210006, 210013, 210016 3.6.1.28 Mg2+ divalent cation requirement is satisfied by Mg2+, Mn2+ or Ca2+ 210006, 210013, 210016 3.6.1.28 Mn2+ divalent cation requirement is satisfied by Mg2+, Mn2+ or Ca2+ 210006, 210013, 210016 3.6.1.28 Mg2+ enzyme is 5% active in the absence of Mg2+ 667797 3.6.1.28 Zn2+ in the presence of Mg2+ at pH 8 667797 3.6.1.28 Zn2+ inhibits at micromolar concentrations at pH 8.0, activates at pH 6.0 655738 3.6.1.28 Ca2+ maximal activation occurs at a cation to substrate ratio of 1:1 210006 3.6.1.28 Mg2+ maximal activation occurs at a cation to substrate ratio of 1:1 210006, 210016 3.6.1.28 Mn2+ maximal activation occurs at a cation to substrate ratio of 1:1 210006 3.6.1.28 Mg2+ required 655738, 751047 3.6.1.28 Mg2+ required for catalytic activity, not required for substrate binding 733393 3.6.1.28 Mg2+ soluble enzyme requires Mg2+, enzyme from membrane is Mg2+-independent 210019 3.6.1.28 Cl- stimulation by anions with the following decreasing order of effectiveness: SCN-, I-, NO3-, Br-, Cl-, membrane-associated enzyme 210006 3.6.1.28 I- stimulation by anions with the following decreasing order of effectiveness: SCN-, I-, NO3-, Br-, Cl-, membrane-associated enzyme 210006 3.6.1.28 SCN- stimulation by anions with the following decreasing order of effectiveness: SCN-, I-, NO3-, Br-, Cl-, membrane-associated enzyme 210006 3.6.1.28 NO3- stimulation by anions with the following decreasing order of effectiveness: SCN-, I-, NO3-, Br-, Cl-, membrane-associated enzyme. The effect of NO3- is maximal at pH 7-8, it is negligible at pH 6.5 210006 3.6.1.28 Br- stimulation by anions with the following order of effectiveness: SCN-, I-, NO3-, Br-, Cl-, membrane-associated enzyme 210006 3.6.1.28 Ca2+ the addition of Ca2+ at 5 mM concentration enhances the rate of thiamine triphosphate hydrolysis by a factor of 17-20 758528 3.6.1.28 Mg2+ the addition of Mg2+ at 5 mM concentration enhances the rate of thiamine triphosphate hydrolysis by a factor of 17-20 758528 3.6.1.28 Mg2+ the enzyme has an absolute requirement for divalent cations, binding of Mg2+ induces only a minor local conformational change 687693 3.6.1.28 Mg2+ the true substrate may be the Mg2+-thiamine-triphosphate complex 210013