The mitochondrial respiratory chain of Rhizopus stolonifer (Ehrenb.:Fr.) Vuill.
Rhizopus stolonifer (Ehrenb.:Fr.) Vuill mitochondria contain the complete system for oxidative phosphorylation, formed by the classical components of the electron transport chain (complexes I, II, III, and IV) and the F(1)F(0)-ATP synthase (complex V). Using the native gel electrophoresis, we have shown the existence of supramolecular associations of the respiratory complexes. The composition and stoichiometry of the oxidative phosphorylation complexes were similar to those found in other organisms. Additionally, two alternative routes for the oxidation of cytosolic NADH were identified: the alternative NADH dehydrogenase and the glycerol-3-phosphate shuttles. Residual respiratory activity after inhibition of complex IV by cyanide was inhibited by low concentrations of n-octyl gallate, indicating the presence of an alternative oxidase. The K(0.5) for the respiratory substrates NADH, succinate, and glycerol-3-phosphate in permeabilized cells was higher than in isolated mitochondria, suggesting that interactions of mitochondria with other cellular elements might be important for the function of this organelle.
Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico, DF, Mexico.
Leobarda
L
Robles-Martínez
María Guadalupe
MG
Guerra-Sánchez
Oscar
O
Flores-Herrera
Ana Niurka
AN
Hernández-Lauzardo
Miguel Gerardo
MG
Velázquez-Del Valle
Juan Pablo
JP
Pardo
D004579:Electron Transport / Q000502:physiology*; D005656:Fungal Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D012233:Rhizopus / Q000378:metabolism*
D005656:Fungal Proteins; D010100:Oxygen