It is generally assumed that glycolysis is remarkably similar among all organisms, prokaryotic and eukaryotic. This view has been extended to protists. However, there is growing evidence that significant deviations from conventional glycolysis occur in protists. Very different species, some parasitic, rely on peculiar enzymes that use pyrophosphate as substrate. In this review, Emmanuel Mertens describes such unusual pyrophosphate metabolism in parasitic protists.