Abstract
Summary
Spectrophotometry of whole cells, microsomal, mitochondrial, and supernatant fractions of Trypanosoma cruzi (Tulahuen strain, culture forms) shows that the microsomal hemoproteins largely contribute to the heme pigments of the parasite. Both the microsomal and mitochondrial fractions have NADH-ferricyanide reductase, NADH-cytochrome c reductase and NADH-oxidase activities, the relative values of which decrease in the order given. Cyanide and antimycin A do not affect the NADH-cytochrome c reductase and NADH-oxidase activities. The mitochondrial fraction shows succinate dehydrogenase activity, which is absent from the microsomal fraction. Spectroscopic and kinetic evidence is put forward for the existence of a NADH-cytochrome b 5 reductase system in the microsomal fraction. In addition, the microsomal fraction contains a CO-binding compound which CO-difference spectrum shows strong absorbance at 420 nm. Mammalian type cytochromes a, b, and c are not detectable in the trypanosomal particulate and soluble fractions.
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