3,5-Diiodothyronine binds to subunit Va of cytochrome-c oxidase and abolishes the allosteric inhibition of respiration by ATP.
The short-term effects of thyroid hormones, which do not occur via gene expression, were postulated to be based on interaction of diiodothyronines with mitochondria. We demonstrate specific binding of labelled 3,5-diiodothyronine to subunit Va of cytochrome-c oxidase from bovine heart. 3,5-Diiodothyronine, and to a small extent triiodothyronine, but not thyroxine and thyronine, abolish the allosteric inhibition of ascorbate respiration of reconstituted cytochrome c oxidase by ATP [Arnold, S. & Kadenbach, B. (1997) Eur. J. Biochem. 249, 350-354]. This abolition of ATP-inhibition by 3,5-diiodothyronine is completely prevented by a monoclonal antibody to subunit Va. The results explain at the molecular level the short-term action of thyroid hormones on basal metabolic rate.
Arnold
S
S
Fachbereich Chemie, Philipps-Universität, Marburg, Germany.
Goglia
F
F
Kadenbach
B
B
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000494:Allosteric Regulation / Q000187:drug effects / Q000502:physiology; D000495:Allosteric Site / Q000502:physiology; D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism; D002417:Cattle; D019069:Cell Respiration / Q000187:drug effects; D003576:Electron Transport Complex IV / Q000378:metabolism*; D007457:Iodine Radioisotopes / Q000378:metabolism; D008929:Mitochondria, Heart / Q000187:drug effects / Q000201:enzymology*; D008958:Models, Molecular; D011485:Protein Binding / Q000502:physiology; D014284:Triiodothyronine / Q000494:pharmacology*
D007457:Iodine Radioisotopes; D014284:Triiodothyronine; D000255:Adenosine Triphosphate; D003576:Electron Transport Complex IV; D001205:Ascorbic Acid