EFFECT OF ZING AND MAGNESIUM IONS IN HIGH CONCENTRATION ON SERUM ALKALINE PHOSPHATASE WITH REFERENCE TO CANCER

This communication reports our studies of the competitive effect of zinc and magnesium ions in relatively high concentrations, on the alkaline phosphatase activity of the scrum of non-cancerous individuals and of those having a malignant tumor. Roche (1, 2, 3) and his associates found that the addition of Zn+ + in a concentration of 10~5 M weakly activated the serum alkaline phosphatase activity in non-cancerous individuals, and in contrast, a slight inhibition was observed in the serum of patients with cancer. Bodansky (4) found that Zn+ + 10~5 M had no effect on the serum alkaline phosphatase activity in individuals either with or without cancer. Similar conclusions were reached by other investigators (5, 6). The activation of alkaline phosphatase activity by magnesium ions has been well established (7, 8, 9, 10) and in general magnesium ions are used to reverse the inhibitory effects of other ions, the exception being beryllium (7, 11). We know of no detailed studies on the effect of the addition of both zinc and magnesium ions on the alkaline phosphatasc activity of serum. Bodansky (4) found that Zn+ + in a concentration of 0.001 M added to serum produced an inhibition of about 50 per cent of serum alkaline phosphatase activity. In our preliminary experiments using 0.001 M Zn+ + as the inhibiting agent, we were able to reverse com-pletely the phosphatase inhibition by the addition of 0.02 M Mg++. This is approximately the same ratio of zinc to magnesium found in human serum. The use of higher concentrations of Zn++ viz: 0.004 M resulted in inhibition of alkaline phosphatase activity of about 80 per cent. The reactivation of alkaline phosphatase activity by magnesium ions is limited, since increasing the concentration of Mg++ above 0.03 M produced no further reversal of the inhibited phosphatase activity. Zin