Adenosine Triphosphate and the Pyruvic and Phosphoglyceric Kinases of the Malaria Parasite Plasmodium lophurae

Abstract

SYNOPSIS. Adenosine triphosphate (ATP) with pyruvate, or adenosine diphosphate with phosphoenolpyruvate, favor the development of Plasmodium lophurae removed from its host erythrocytes and kept extracellularly in vitro. It seemed possible that the parasites might be deficient in enzymes of the glycolytic cycle concerned with the generation of ATP. The ATP content of duck erythrocytes infected with P. lophurae was lower than that of uninfected cells. Infected erythrocytes, however, had somewhat higher contents of both pyruvic kinase and phosphoglyceric kinase than did uninfected ones. Both of these enzymes could be found in the free parasites. Furthermore, the pyruvic kinase of the free parasites was inactivated by freezing and thawing, whereas that of the host erythrocyte was not affected. It will be necessary, therefore, to look further for the basis for the favorable effect of ATP with pyruvate on parasites developing extracellularly in vitro.