Alkaline phosphatase activity in plasma of pregnant chagasic patients

The kinetic properties of plasma placental alkaline phosphatase patients with Chagas' disease were studied. When Cl2Mg was used as activator the same increase of activity (17-20%) was found in the chagasic and non chagasic groups. The enzyme was not inhibited by F-ion in any of the groups. No significant differences were detected between the two groups (chagasic and non chagasic) when the enzyme was treated with inhibitors such as EDTA and L-phenylalanine. However, when the CN-ion was used, the enzyme of the normal pregnant women followed a Michaelian curve, whereas in the chagasic group a sigmoideal plot was observed. Thus, the Hill coefficient was 1.1 for the normal group and over 1.5 for the chagasic.