ABSTRACT
Proteolytic activity appears to be required for malaria parasites to carry out a number of functions, particularly during the asexual or erythrocytic stage of infection. The erythrocytic malarial life cycle is initiated by the invasion of host erythrocytes by free merozoites (Garnham, 1988). The intraerythrocytic parasites then develop from small ring stage organisms to larger, more metabolically active trophozoites, and then to multinucleated schizonts. The erythrocytic cycle is completed when mature schizonts rupture the erythrocytes, releasing numerous invasive merozoites. Asexual-stage parasites require proteolytic activity for the hydrolysis of host and parasite proteins during erythrocyte invasion and rupture, the degradation of host haemoglobin into free amino acids by trophozoites, and routine intracellular housekeeping. While some of these functions might be accomplished by host proteinases, there is evidence that a number of malarial proteinases are involved.
