The oxidase systems of Ascaris-muscle mitochondria

Abstract

1. The oxidase systems of Ascaris-muscle mitochondria were investigated by polarographic and spectroscopic techniques. 2. Spectrophotometric studies at −196° revealed that Ascaris-muscle mitochondria contained low levels of substrate-reducible a-, b- and c-type cytochromes. Cytochrome a₃, present in very low concentrations, was shown to be functional by photochemical action spectrum. 3. Ascaris-muscle mitochondria oxidized (in decreasing order of respiratory activity) succinate, malate, NADH and α-glycerophosphate with H₂O₂ as end-product. 4. The antimycin A-insensitive ascorbate-tetramethyl-p-phenylenediamine (TMPD) oxidase activity was inhibited 33% by 1.0 mM CN⁻, 58% by CO and 100% by CO plus 1.0 mM CN⁻. CO inhibited 50% of succinate oxidation. 5. Fluorescence spectrum confirms and further identifies the two flavin components involved with malate oxidation in Ascaris-muscle mitochondria.