The Alkaline Phosphatase is purified by affinity chromatography, which results in an enzyme of high specific activity and purity.
Alkaline Phosphatase is Dimeric protein having a molecular weight of 140 kDa, one Zn++ ion is tightly bound to each subunit, and another less tightly bound is involved in the catalytic reaction. Mg++ stimulates the catalysis. The binding site for Mg++ is different to that of Zn++, but will be occupied by excess Zn++ followed by loss of enzyme activity.