Trypanosomatid hydrogen peroxidase metabolism

The rate of whole cell H2O2 metabolism in several salivarian and stercorarian trypanosomes and Leishmania species was measured. These cells metabolized H2O2 at rates between 2.3 and 48.2 nmol/10(8) cells per min depending upon the species employed. H2O2 metabolism was largely insensitive to NaN3, implying that typical catalase and peroxidase haemoproteins are not important in H2O2 metabolism. The metabolism of H2O2, however, was almost completely inhibited by N-ethylmaleimide. In representative species, H2O2 metabolism was shown to occur through a trypanothione-dependent mechanism.