Plasmodium falciparum phosphoenolpyruvate carboxykinase is developmentallyregulated in gametocytes

Plasmodium species have the capacity to fix carbon dioxide during intracell ular development. This process contributes to the pool of free amino acids and metabolites, which are the end products of glucose metabolism in the ma laria parasite. A gene encoding phosphoenolpyruvate carboxykinase (PEPCK), an enzyme known to catalyze CO2 fixation was identified in the genome of th e human parasite Plasmodium falciparum by DNA microarray analysis experimen ts and was cloned and characterized. PfPEPCK is a 66.2 kDa, ATP-dependent e nzyme which is closely related to PEPCK from plants and yeast but markedly different from the host enzyme human PEPCK. PfPEPCK transcript anti active enzyme levels are upregulated in the transmissible and zygote stages of par asite development relative to the asexual blood stages. Elevated expression of PfPEPCK during the extracellular zygote phase of P. falciparum developm ent within the microenvironment of the mosquito midgut may reflect a glucos e-rare medium and suggests a possible switch in carbohydrate metabolism to a gluconeogenesis pathway. (C) 2000 Elsevier Science B.V. All rights reserv ed.