Plasmodium falciparum is the causative agent of malaria tropica in man. 
Biochemical studies were focused on the asexual, intraerythrocytic stages of P. 
falciparum, because of their role in the clinical phase of the disease and the 
possibility of propagation in a cell culture system. In this report, we describe 
the in-culture labeling of malarial glycolipids and the analysis of their 
hydrophilic moieties. They were identified as glycosylphosphatidylinositols 
(GPIs) by: 1) labeling with [3H]mannose, [3H]glucosamine, and [3H]ethanolamine 
and 2) sensitivity toward glycosylphosphatidylinositol-specific phospholipase D, 
phospholipase A2, and nitrous acid. Malarial GPIs are shown to be unaffected by 
treatment with phosphatidylinositol-specific phospholipase C, regardless of 
prior treatment with mild base commonly used for inositol deacylation. Two 
candidates for putative GPI-anchor precursors to malarial membrane proteins with 
the structures ethanolamine-phosphate-6(Man alpha 1-2)Man alpha 1-2Man alpha 
1-6Man alpha 1-4 GlcN-PI (Pfg1 alpha) and ethanolamine-phosphate-6Man alpha 
1-2Man alpha 1-6Man-alpha 1-4-GlcN-PI (Pfg1 beta) were identified.