RELATIONSHIPS BETWEEN STOICHIOMETRY OF OXIDATIVE-PHOSPHORYLATION AND PHOSPHORYLATION POTENTIAL OF RAT-LIVER MITOCHONDRIA AS FUNCTIONS OF RESPIRATORY STATE
RELATIONSHIPS BETWEEN STOICHIOMETRY OF OXIDATIVE-PHOSPHORYLATION AND PHOSPHORYLATION POTENTIAL OF RAT-LIVER MITOCHONDRIA AS FUNCTIONS OF RESPIRATORY STATE
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DOI：
10.1016/0014-5793(74)80004-9
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发表时间：
1974-01-01
期刊：
影响因子：
3.5
通讯作者：
BOTTOMS, D
中科院分区：
文献类型：
--
作者：
DAVIS, EJ;LUMENG, L;BOTTOMS, D
The characteristics of the mitochondrial adenine nucleotide exchange carrier have been studied in detail (see eg ref.[11). Exchange of ADP and ATP across the mitochondrial inner membrane, mediated by this carrier, appears to be the rate-limiting step for oxidative phosphorylation under conditions which obtain in vivo [l-3]. The asymmetry in the specificity of the transport of adenine nucleotide results in an asymmetric distribution of ADP and ATP on the two sides of the membrane, the ATP/ADP ratio being greater outside the mitochondria than inside [1, 4, 51. As predicted by Klingenberg and co-workers [4] the formation and maintenance of this gradient of phosphorylation potential (ATP/ADP X Pi) would be expected, on thermodynamic grounds, to consume metabolic energy.The present communication reports the results of experiments carried out with liver mitochondria under conditions in which respiration is controlled by a constant and limiting supply of ADP, in such a manner that in vivo conditions are closely simulated: ie,(a) a high extramitochondrial phosphorylation potential is maintained, and is constant throughout an incubation; and (b) the concentrations of inorganic phosphate and of extramitochondrial adenine nucleotides are held constant and within the physiological range of concentration. The data are interpreted as being a direct estimation of energy requirement for maintenance of a high cytosolic phosphorylation potential.
