6.3.4.2 Co2+ stimulates at a lower level than Mg2+ 649002 6.3.4.2 Mg2+ - 674909, 690817, 694484, 694934 6.3.4.2 Mg2+ absolute requirement 649003 6.3.4.2 Mg2+ absolutely dependent on 648982 6.3.4.2 Mg2+ assay with 10 mM Mg2+ 677028 6.3.4.2 Mg2+ assay with 10 mM MgCl2 672395, 674816, 674886, 674909 6.3.4.2 Mg2+ assay with 30 mM MgCl2 674786 6.3.4.2 Mg2+ dependent on 4 mM Mg2+ for maximal activity 648999 6.3.4.2 Mg2+ dUTP-dependent activity is dependent on Mg2+, maximal activity at 4 mM 648978 6.3.4.2 Mg2+ required, no activity in absence of 648987 6.3.4.2 Mg2+ required, the activation curve for free Mg2+ concentration is greatly dependent on whether the concentration of ATP and UTP are near saturating 648977 6.3.4.2 Mg2+ sequence displays a Mg2+ binding site 746547 6.3.4.2 Mg2+ the enzyme requires more Mg2+ for full catalytic activity than required simply to complex the nucleotide substrate. Half-saturation value for Mg2+ is 2.6 mM for the reaction with NH4+ and 2.4 mM for the glutamine-dependent reaction 649002 6.3.4.2 Mn2+ stimulates at a lower level than Mg2+ 649002