Control of choline oxidation by rat-liver mitochondria.
The steady-state concentrations of choline and its reaction products in intact rat-liver mitochondria were determined under different conditions. From these measurements, it is concluded that in a sucrose medium choline dehydrogenation and betaine aldehyde dehydrogenation are the rate-limiting steps in overall choline oxidation under "State-3" or uncoupled conditions, respectively. Ageing of the mitochondria leads to changes in the mitochondrial membrane, resulting in a markedly different pattern of oxidation products. This finding explains why rotenone inhibits oxygen uptake with choline as substrate in fresh but not in aged mitochondria.
D000090:Acetoacetates / Q000494:pharmacology; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000249:Adenosine Monophosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D000818:Animals; D001622:Betaine / Q000378:metabolism; D002794:Choline / Q000378:metabolism*; D004140:Dinitrophenols / Q000494:pharmacology; D006885:Hydroxybutyrates / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects; D051381:Rats; D012402:Rotenone / Q000494:pharmacology
D000090:Acetoacetates; D004140:Dinitrophenols; D006885:Hydroxybutyrates; D012402:Rotenone; D001622:Betaine; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000445:Aldehyde Oxidoreductases; D002794:Choline