📒 Demin 2001
Kinetic Modeling of Energy Metabolism and Superoxide Generation in Hepatocyte Mitochondria1
THE KINETIC MODEL
- 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)
RESULTS AND DISCUSSION
- 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
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. ↩︎