Carnitine cycle in brown adipose tissue mitochondria as a tool for studying the regulatory role of fatty acids in the uncoupling protein function.
A concerted function of purine nucleotide (PN) binding and fatty acid (FA) release from the uncoupling protein (UP) resulting in the maximum coupling (potential) of brown adipose tissue (BAT) mitochondria was demonstrated. The uncoupling effect of FA was studied (at 4 mM MgCl2): 17 nmol oleate per mg protein caused a slight uncoupling with 8.9 mM ATP but with ATP below 3.6 mM almost total uncoupling was achieved. This shows that the PN-controlled gate can be stabilized in the closed conformation (with 8.9 mM ATP), also when FA is bound to UP. The sensitivity of the FA effect to ATP proves that oleate directly interacts with UP. The closed conformation of the H+ channel of UP is then abolished by oleate when a lower free ATP concentration is maintained outside.
Jezek
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P
Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
Krasinskaya
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IP
Smirnova
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Drahota
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Z
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D002331:Carnitine / Q000378:metabolism*; D002352:Carrier Proteins; D006224:Cricetinae; D005230:Fatty Acids, Nonesterified / Q000502:physiology*; D006153:Guanosine Diphosphate / Q000494:pharmacology; D006706:Homeostasis; D007473:Ion Channels; D007700:Kinetics; D008565:Membrane Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D024101:Mitochondrial Proteins; D019301:Oleic Acid; D009829:Oleic Acids / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects; D014475:Uncoupling Agents / Q000494:pharmacology*; D000071256:Uncoupling Protein 1
D002352:Carrier Proteins; D005230:Fatty Acids, Nonesterified; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D009829:Oleic Acids; D014475:Uncoupling Agents; D000071256:Uncoupling Protein 1; D006153:Guanosine Diphosphate; D019301:Oleic Acid; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D002331:Carnitine