Structural and functional organization of Complex I in the mitochondrial respiratory chain.
Metabolic flux control analysis of NADH oxidation in bovine heart submitochondrial particles revealed high flux control coefficients for both Complex I and Complex III, suggesting that the two enzymes are functionally associated as a single enzyme, with channelling of the common substrate, Coenzyme Q. This is in contrast with the more accepted view of a mobile diffusable Coenzyme Q pool between these enzymes. Dilution with phospholipids of a mitochondrial fraction enriched in Complexes I and III, with consequent increased theoretical distance between complexes, determines adherence to pool behavior for Coenzyme Q, but only at dilution higher than 1:5 (protein:phospholipids), whereas, at lower phospholipid content, the turnover of NADH cytochrome c reductase is higher than expected by the pool equation.
Bianchi
Cristina
C
Universtiy of Bologna, Bologna, Italy.
Fato
Romana
R
Genova
Maria Luisa
ML
Parenti Castelli
Giovanna
G
Lenaz
Giorgio
G
D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000737:chemistry / Q000201:enzymology; D004579:Electron Transport; D042967:Electron Transport Complex I / Q000737:chemistry* / Q000502:physiology*; D014450:Electron Transport Complex III / Q000378:metabolism; D008929:Mitochondria, Heart / Q000201:enzymology* / Q000648:ultrastructure; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D010743:Phospholipids / Q000032:analysis; D013367:Submitochondrial Particles / Q000201:enzymology; D014451:Ubiquinone / Q000378:metabolism
D010743:Phospholipids; D009243:NAD; D014451:Ubiquinone; D042967:Electron Transport Complex I; D014450:Electron Transport Complex III