[Formation of complexes of superoxide anion radicals with Ca++]

It has been shown that Ca2+ can form complexes with superoxide anion radicals (O(-2)). The constant of this interaction is 3 10(4)-5.5 10(4) M-1s-1. Mg2+ and Zn2+ cations do not form complexes with O(-2). It is concluded that Ca2+ may be involved in the control of O(-2) content in the cell.