5.1.3.37 Ca2+ absolutely required, optimum concentration 1 mM 733609 5.1.3.37 Ca2+ required for activity, all the mannuronan C5-epimerases of Azotobacter vinelandii show differences in concentration of calcium ions needed for full activity, overview 747457 5.1.3.37 Ca2+ required, enhances gelation by 1.7fold following rSjC5-VI activity 746698 5.1.3.37 Ca2+ required, optimum concentration 0.8 mM. The Ca2+ requirement of domain AlgE1-1 is much higher (optimum around 3 mM) than that of whole AlgE1, while domain AlgE1-2 needs slightly more Ca2+ than AlgE1 for optimal activity 734128 5.1.3.37 Ca2+ required, optimum concentration 1-3 mM 734129 5.1.3.37 Ca2+ the epimerization reaction is Ca2+ dependent, and both the A and R modules bind this cation. The R modules appear to reduce the Ca2+ concentration needed for full activity and also stimulate the reaction rate when positioned both N- and C-terminally 734060 5.1.3.37 Mg2+ at Ca2+ concentrations lower than optimum, the addition of Sr2+ or Mg2+ has a stimulatory effect, but Mg2+ is not able to substitute for Ca2+ when no calcium is added 734128 5.1.3.37 additional information no Ca2+ ions required for activity, and the Ca2+-alginate complex is not a substrate for the enzyme 733323 5.1.3.37 additional information no effect by 1 mM of Mg2+, Sr2+, Li+, and Ba2+ 746698 5.1.3.37 NaCl activates best at 300 mM 746698 5.1.3.37 Sr2+ may partly substitute for Ca2+. At Ca2+ concentrations lower than optimum, the addition of Sr2+ or Mg21 has a stimulatory effect 734128 5.1.3.37 Sr2+ may substitute for Ca2+ with an efficiency of about 30% 734129