Vitamin C biosynthesis in trypanosomes: a role for the glycosome.

ABSTRACT: The capacity to synthesize vitamin C (ascorbate) is widespread in eukaryotes but is absent from humans. The last step in the biosynthetic pathway involves the conversion of an aldonolactone substrate to ascorbate, a reaction catalyzed by members of an FAD-dependent family of oxidoreductases. Here we demonstrate that both the African trypanosome, Trypanosoma brucei, and the American trypanosome, Trypanosoma cruzi, have the capacity to synthesize vitamin C and show that this reaction occurs in a unique single-membrane organelle, the glycosome. The corresponding T. brucei flavoprotein (TbALO) obeys Michaelis-Menten kinetics and can utilize both L-galactono-gamma-lactone and D-arabinono-gamma-lactone as substrate, properties characteristic of plant and fungal enzymes. We could detect no activi

SUBMITTER: Wilkinson SR 

PROVIDER: S-EPMC1187986 | biostudies-literature | 2005 Aug

REPOSITORIES: biostudies-literature