📒 Demin 2001

Kinetic Modeling of Energy Metabolism and Superoxide Generation in Hepatocyte Mitochondria1



  • The first group (IMM): intermediates of the Q cycle.
  • The second group (matrix): metabolites like proton, phosphate, magnesium, potassium, ATP, ADP
  • If the low-potential heme of cytochrome b is reduced, then semiquinone remains bound with NIC until bl becomes oxidized.
  • electrons flow from the low-potential heme bl to the high-potential heme bh
  • the mitochondrial matrix is a proton buffer, we approximated its buffer characteristics by three proton-binding groups B1, B2, and B3 with p K for protons changing from 6.7 to 8.7:

  • Any stage including the transfer of an electrical charge through a membrane produces the membrane potential (∆Ψ)

Other complexes



  • both the respiration rate and the rate of SOX generation decreases with the decrease of ∆Ψ

  • The production of SOX sharply increases when the potential grows from 155 mV to 180 mV

  • by increasing the concentration of extramitochondrial phosphate (Fig. 5a) or by decreasing the concentration of extramitochondrial potassium (not shown), we revealed that at the same potential values, the rate of superoxide generation decreases

  • the rate of superoxide generation as a function of PMF


  1. Demin OV, Gorianin II, Kholodenko BN, Westerhoff HV. Kinetic modeling of energy metabolism and generation of active forms of oxygen in hepatocyte mitochondria. Mol Biol (Mosk). Dec 2001;35(6):1095–104. ↩︎