Role of Heme and Heme-Proteins in Trypanosomatid Essential Metabolic Pathways

Figure 2

Heme biosynthesis in trypanosomatids (revisited by Kořený et al. [3]). Leishmania spp. can perform the last three steps in heme synthesis, catalyzed by coproporphyrinogen oxidase, protoporphyrinogen oxidase, and ferrochelatase, localized into the mitochondria. T. cruzi and T. brucei cannot perform any step for heme B biosynthesis and must import heme compounds (hemoglobin, hemin, etc.) from their hosts. They can modify heme B to obtain heme A and cytochrome c, although this has been described only for T. cruzi, it is probable that L. major and T. brucei have the same capability. Mechanisms by which these trypanosomatids couple heme to apoproteins or regulate heme compounds levels to avoid toxic effects are unknown.