Mg2+
more than 5 mM MgCl2 is required for maximum activity. The enzyme reaction is unable to proceed without MgCl2
Mn2+
38% activity (relative to the activity in the presence ofMg2+) is retained in the presence of 5 mM Mn2+
more
no activity is observed for Fe2+, Co2+, Zn2+, Ni2+, or Cu2+