CALCIUM-ACTIVATED NEUTRAL PROTEASE AND CALCIUM-ATPASE IN GLUCOSE-6-PHOSPHATE-DEHYDROGENASE DEFICIENCY HEMIZYGOTES

To study the mechanism of haemolysis in G6PD deficient erythrocytes, s tudies-were undertaken in G6PD deficiency and in normal erthrocytes ar tificially loaded with calcium. Significantly increased concentrations of calcium, calcium activated neutral protease (CANP) and calcium ATP ase were found in patients of G6PD deficiency. However, the membrane b ound calcium, the total glycoprotein and sulphydryl groups of membrane were observed to be decreased. Similar results were also observed in the normal erythrocytes when loaded with calcium. These results point to the role of the proteolytic process in membrane modification, and a ltered membrane permeability during the haemolytic process. Our observ ations in G6PD deficiency and in in vitro point to the existence of a calcium dependent proteolytic preconditioning of erythrocyte accelerat ing the haemolysis.