Affiliations: Universtiy of Bologna, Bologna, Italy
Note: [] Address for correspondence: Dipartimento di Biochimica "G.
Moruzzi", Università di Bologna, Via Irnerio 48, 40126 Bologna, Italy. Tel.:
+39 051 2091229; Fax: +39 051 2091217; E-mail: [email protected]
Abstract: 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.
Keywords: mitochondria, Coenzyme Q pool, supercomplex, flux control, Complex I, Complex III
Journal: BioFactors, vol. 18, no. 1-4, pp. 3-9, 2003
