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8552977 
Journal Article 
Affinities of ATP for the dinitrophenol-induced ATPase 
Verdouw, H; Bertina, RM 
1973 
1 
Biochimica et Biophysica Acta. Bioenergetics
ISSN: 0005-2728
EISSN: 1879-2650 
325 
3 
385-396 
English 
1. 1. The effect of Mg2+ on ATP-dependent processes catalysed by intact rat-liver mitochondria can be explained quantitatively by the formation of Mg-ATP complexes that cannot act as a substrate for the adenine nucleotide translocator. 2. 2. The dinitrophenol-induced ATPase is characterized by two affinities of ATP: Km(1) = 6.7 μM and Km(2) = 63 μM, which contribute to the extent of 70% and 30%, respectively, to the total ATPase activity under the standard conditions employed. 3. 3. Km(1) of ATP is competitively increased by atractyloside, and is insensitive to changes in cation concentration or to oligomycin or aurovertin. 4. 4. Km(2) is as sensitive to atractyloside as the Km(1) and is also insensitive to oligomycin. However, it is increased by decreasing the cation concentration, and disappears in the presence of aurovertin. 5. 5. It is proposed that two conformations of the adenine nucleotide translocator exist, characterized by their different affinities for ATP. The distribution of the enzyme over these two conformations appears to be a function of the energy state of the mitochondria (coupled or uncoupled). © 1973.