The competitive effect of adenosine-5'-triphosphate against the stimulating and inhibiting actions of 2,4-dinitrophenol on the mitochondrial respiration.

Effect of ATP and substrates on 2,4-dinitrophenol-induced adenosine triphcsphatase (E. C. 3.6. 1. 4.) activity and respiration of isolated rat liver mitochondria has been investigated. 1. The oxidation of sodium succinate inhibited the action of 2, 4-DNP on the induction of adenosine triphosphatase activity in the mitochondria. 2. A moderately large amount of sodium succinate restored the suppressed mitochondrial respiration due to 2, 4-DNP. 3. Adenosine-5’-triphosphate (ATP) restored quantitatively the released and inhibited mitochondrial respiration due to 2,4-DNP, and its prior addition prevented also quantitatively the action of 2,4-DNP on the mitochondrial oxygen up-take. These ATP effects were oligomycin sensitive, and they were considered to manifest their actions through the phosphorylation system. ∗PMID: 4242844 [PubMed indexed for MEDLINE] Copyright c ©OKAYAMA UNIVERSITY MEDICAL SCHOOL Acta Med. Okayama 23, 227-235 (1969) THE COMPETITIVE EFFECT OF ADENOSINE.5'.TRIPHOS. PHATE AGAINST THE STIMULATING AND INHIBI.· TING ACTIONS OF 2,4.DINITROPHENOL ON THE MITOCHONDRIAL RESPIRATION O. HATASE, G. YAMAMOTO and T. ODA Department oj Biochemistry, Cancer Inrtitute, Okayama University Medical School, Okayama, Japan (Director: Proj. T. Oda) Received jor publication, April 24, 1969 There are two major theories proposed to reveal the coupling mechanism of oxidative phosphorylation, but no direct evidence has been given to decide which one is correct. One is the chemical coupling hypothesis, the flow sheet type theory, which explains that the free energy driven from the electron transfer system is converted to the assumed nonphosphorylated high energy intermediate and is used finally for binding ADP and inorganic phosphate (1, 2, 3). In this hypothesis; I, the assumed nonphosphorylated high energy intermediate has not been generally approved; 2, the uncoupling agents that have no common chemical properties can perform the cleaving action of electron transfer system and phosphorylating system; 3, the swelling and shrinkage of mitochondria are difficult to be understood by this concept. On the contrary MITCHELL proposed the chemi-osmotic coupling hypothesis, which presumed electron and proton motive force gradient between the inner and outer phases across the inner mitochondrial membrane (4, ,5,6). The most fundamental role of this gradient produced by the intact membrane structure (the outer, membraneous, and inner phases) and the electron transfer system is the driving force of the synthesis of ATP physico-chemically from ADP and inorganic phosphate by the reversible adenosine triphosphatase (ATPase). 2,4-DNP, one of the most representative uncoupling agents, stimulates and inhibits the mitochondrial respiration. The present paper describes a newly observed effect of ATP that showed competition against the actions of 2, 4-DNP on oxygen up-take of mitochondria and its correlation to coupling mechanism. -_..._--_.._------ATP; adenosine-Y-triphospl:ate, ADP; adenosine-5'.diphopbate, 2,4-DNP; 2,4-dinitrophenol, isooctyl-DNP; isooctyl-dinitrophenol, EDTA; disodium ethylenediaminetetraacetate, Tris; tris (hydroxymetbyl)-aminometr.ane, ATPase; adenosine triphosphatase (E. C. 3. 6.1.4. ).