Partial Resolution of the Enzymes Catalyzing Oxidative Phosphorylation XXVIII. THE RECONSTITUTION OF THE FIRST SITE OF ENERGY CONSERVATION
Abstrak
Abstract 1. The ability to phosphorylate ADP during oxidation of NADH by ubiquinone-1 was restored to the NADH-ubiquinone reductase complex by combining the latter with phospholipids and a hydrophobic protein fraction derived from bovine heart mitochondria. 2. Phosphorylation was abolished by rotenone, uncoupling agents, or rutamycin. The efficiency of ATP formation was as high as 0.5 mole per mole of NADH oxidized under optimal conditions. 3. Reconstitution of phosphorylation had an absolute requirement for phosphatidylethanolamine and a partial requirement for phosphatidylcholine, a molar ratio of approximately 4:1 being optimal. A much more marked requirement for phosphatidylcholine was observed in the presence of low concentrations of cardiolipin (0.05 to 1.5% of the total phospholipid). In the presence of cardiolipin, an equal molar ratio of phosphatidylethanolamine to phosphatidylcholine gave the highest phosphorylation efficiency. 4. The NADH-ubiquinone reductase complex is oriented in the reconstituted vesicles such that approximately 50% of the molecules can react with added NADH. Reaction of all the molecules with NADH occurs in the presence of 0.5% deoxycholate. 5. Phosphorylation efficiency can be significantly improved by purification of the vesicles on sucrose density gradients.
Topik & Kata Kunci
Penulis (2)
C. Ragan
E. Racker
Akses Cepat
- Tahun Terbit
- 1973
- Bahasa
- en
- Total Sitasi
- 927×
- Sumber Database
- Semantic Scholar
- DOI
- 10.1016/s0021-9258(19)44145-8
- Akses
- Open Access ✓