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O'Donoghue 2009 Biochim Biophys Acta

From Bioblast
Publications in the MiPMap
O'Donoghue N1, Sweeney T, Donagh R, Clarke KJ, Porter RK (2009) Control of choline oxidation in rat kidney mitochondria. Biochim Biophys Acta 1787:1135-9.

ยป PMID:19426704 Open Access

O'Donoghue N1, Sweeney T, Donagh R, Clarke KJ, Porter RK (2009) Biochim Biophys Acta

Abstract: Choline is a quaternary amino cationic organic alcohol that is oxidized to betaine in liver and kidney mitochondria. Betaine acts as an intracellular organic osmolyte in the medulla of the kidney. Evidence is provided that kidney mitochondria have a choline transporter in their inner membrane. The transporter has a Km of 173+/-64 microM and a Vmax of 0.4+/-0.1 nmol/min/mg mitochondrial protein (at 10 degrees C). Uptake of choline is not coupled to betaine efflux. Transporter activity demonstrates a dependence on membrane potential and choline transport is inhibited by hemicholinium-3. Steady-state oxygen consumption due to choline oxidation in kidney mitochondria was measurable at 37 degrees C (125+/-6 pmol O2/min/mg mitochondrial protein), in the absence of other mitochondrial electron transport chain substrates and the choline transporter was shown to be the major site of control (96+/-4%) over choline oxidation flux in isolated kidney mitochondria. We conclude that the choline transporter in rat kidney mitochondria is the major site of control over the production of the organic osmolyte, betaine.

โ€ข Bioblast editor: Gnaiger E โ€ข O2k-Network Lab: IE Dublin Porter RK

Labels: MiParea: Respiration 

Organism: Rat  Tissue;cell: Kidney  Preparation: Isolated mitochondria 

Coupling state: LEAK, OXPHOS  Pathway: Other combinations