3.5.4.4 Ba2+ - 686577 3.5.4.4 CoSO4 - 209631 3.5.4.4 Fe2+ the activity found in the enzymes expressed with added Zn(II) and added Fe(II) are 2fold higher than when expressed with Ni(II) or without additional metal 727779 3.5.4.4 Fe3+ - 209627, 209630 3.5.4.4 Hg2+ - 686577 3.5.4.4 K+ - 209616 3.5.4.4 Li+ - 209613 3.5.4.4 lithium ion - 686577 3.5.4.4 Mg2+ 91% inhibition 686577 3.5.4.4 Mg2+ activates 686612