Cholate separates the catalytic and malonyl-CoA-binding components of carnitine palmitoyltransferase from liver outer mitochondrial membranes
| Autor: | Iraj Ghadiminejad, David Saggerson |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Male
Detergents Biophysics Polysorbates Mitochondria Liver macromolecular substances Cholic Acid In Vitro Techniques Biochemistry Catalysis chemistry.chemical_compound Endocrinology medicine Inner membrane Animals Carnitine O-palmitoyltransferase Carnitine Sodium Cholate Inner mitochondrial membrane Carnitine O-Palmitoyltransferase Chemistry Cholic Acids Rats Inbred Strains Intracellular Membranes Rats Malonyl Coenzyme A enzymes and coenzymes (carbohydrates) Malonyl-CoA Membrane Solubility lipids (amino acids peptides and proteins) Bacterial outer membrane medicine.drug |
| Zdroj: | Biochimica et biophysica acta. 1083(2) |
| ISSN: | 0006-3002 |
| Popis: | Sodium cholate was used as an anionic detergent to discriminate the two components of liver overt carnitine palmitoyltransferase (CPT1); namely a catalytic entity and a regulatory component that bound malonyl-CoA. Cholate solubilized approx. 40% of the malonyl-CoA binding entity from mitochondrial outer membranes without appreciable solubilization of CPT1 activity. Cholate did not interfere with binding of [14C]malonyl-CoA to outer membranes or to crude total mitochondrial membrane fractions. By contrast, the non-ionic detergent Tween-20 was ineffective in solubilizing the malonyl-CoA binding entity and also substantially interfered with the binding of [14C]malonyl-CoA. Both detergents appeared to cause total disengagement of the malonyl-CoA binding entity from the catalytic entity of CPT1 only when some inner membrane material was present. 'Reconstitution' experiments were performed in which a malonyl-CoA sensitivity conferring factor in cholate extracts from outer membranes was associated with CPT derived from inner membranes (CPT2). The IC50 for inhibition of CPT2 by malonyl-CoA in this artificial system was similar to that observed with CPT1 in situ in outer membranes. Extracts containing malonyl-CoA sensitivity conferring factor derived from outer membranes of fed or 48 h fasted rats were associated with CPT2 derived from fed rats. The outer membrane extracts from fasted animals conferred a lower maximum responsiveness to malonyl-CoA, but appeared to have a higher affinity for CPT2 than the extracts from fed rats. These results suggest that physiological state can alter the intrinsic properties of the malonyl-CoA sensitivity confering factor. |
| Databáze: | OpenAIRE |
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