1. The energy-independent exchange of alkali metal cations against protons was investigated in intact and disintegrated mitochondria. The exchange is not specific for different alkali metal ions.2. In intact mitochondria the apparent K(m) for the energy-independent exchange range from 5 to 25 mM (Cs(+), Rb(+), K(+) 5-10 mM; Na(+) 15 mM; Li(+) 20 mM). At all ions studied the maximum release of protons was 15-20 nval/mg protein.3. In disintegrated mitochondria there are no differences between the alkali metal ions (apparent K(m) 30 mM; maximum H(+)-release 50 nval/mg protein).4. Directly accessible binding sites seem to exist in the outer membrane. Binding sites in the inner membrane are accessible only after disintegration, but not after addition of valinomycin + rotenone.
Lutze
G
G
Physiol.-chem. Institut der Medizinischen Akademie Magdeburg, 301, Magdeburg, DDR
Liese
W
W
Kunz
W
W
Uber einen energieunabhängigen austausch der alkali-ionen Li(+), Na(+), K(+), Rb(+) und Cs(+) GEGEN H(+) in der membran intakter und desintegrierter rattenlebermitochondrien.