Lardy 1952 J Biol Chem
| Lardy HA, Wellman H (1952) Oxidative phosphorylations; rΓ΄le of inorganic phosphate and acceptor systems in control of metabolic rates. J Biol Chem 195: 215-224. |
Β» PMID: 14938372; Open Access
Lardy HA, Wellman H (1952) J Biol Chem
Abstract: Rat liver mitochondria, prepared in 0.25 M sucrose and fortified with ATP, magnesium, and phosphate buffer, oxidize proline, glutamate, citrate, pyruvate, Ξ±-ketoglutarate, succinate, malate, and Ξ²-hydroxybutyrate at extremely slow rates. The rates of oxidation apparently are limited by the rate of transfer or hydrolysis of high energy phosphate compounds whose synthesis is coupled with the oxidative electron transport. The rates of oxidation of all these substrates are greatly enhanced by phosphate acceptor systems such as adenylic acid, ADP, creatine plus its phosphorylating enzyme, or glucose plus hexokinase. With glucose and hexokinase as the acceptor system, P:O ratios of about 3 were obtained with glutamate, citrate, Ξ±-ketoglutarate, pyruvate, and Ξ²-hy- droxybutyrate as the substrate in systems in which the Krebs cycle of oxidations is proceeding. 2,4-Dinitrophenol, an agent which accelerates the breakdown of NP compounds, also accelerates the rate of oxygen consumption with each of the above substrates. The initial rate of oxidation of caprylate to acetoacetate is enhanced by ~P acceptors. This oxidation resulted in P: 0 ratios of 1.1 to 1.4 with creatine as the ~P acceptor and of 1.7 to 2 with glucose as the ~P acceptor.
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