Characterisation of glutamine uptake in rat liver mitochondria.
Glutamine is taken up by rat liver mitochondria in an electroneutral manner with a Km of 3.3 mM and a Vmax of 33 nmol x min-1 x mg-1 at 10 degrees C. The uptake is driven by the mitochondrial pH/cytosolic pH difference in isolated mitochondria, as well as in the intact rat liver. The rate of uptake is stimulated at a more alkaline matrix pH due to a stimulation of mitochondrial glutaminase. Our data confirm the notion that glutamine metabolism is regulated by pH, not only at the site of its metabolism but also through regulation of its transport systems.
Soboll
S
S
Institut für Physiologische Chemie I, Universität Düsseldorf, Federal Republic of Germany.
Lenzen
C
C
Rettich
D
D
Gründel
S
S
Ziegler
B
B
D000818:Animals; D001692:Biological Transport; D003600:Cytosol / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D009550:Nigericin / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D013386:Succinates / Q000494:pharmacology
D013386:Succinates; D005973:Glutamine; D009550:Nigericin; D011188:Potassium