Open AccessUsing 2′(3′)‐O‐Trinitrophenyl Derivatives of Adenine Nucleotides to Study the Structure and Mechanism of Functioning of Soluble Mitochondrial ATPase
Author(s) -
KORMER Zinaida S.,
KOZLOV Igor A.,
MILGROM Yakov M.,
NOVIKOVA Irina Yu.
Publication year - 1982
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1982.tb05808.x
Subject(s) - picric acid , chemistry , nucleotide , atpase , molecule , fluorescence , adenine nucleotide , binding site , stereochemistry , biophysics , enzyme , biochemistry , biology , organic chemistry , physics , quantum mechanics , gene
The 2′(3′)‐O‐trinitrophenyl (N 3 ph) derivatives of the adenine nucleotides are strong competitive inhibitors of isolated mitochondrial ATPase (factor F 1 ). K i decreases in the order N 3 phAdo >N 3 phAMP >N 3 phADP and is equal to 8 nM for N 3 phADP. Picric acid, which activates the ATPase reaction of factor F 1 without changing the K m(app.) , prevents the inhibiting action of N 3 phADP. At pH 7.6 the inhibition of factor F 1 is accompanied by the binding of one molecule of N 3 phADP to a molecule of the enzyme. This binding leads to changes in the absorption spectrum, but not in the intensity of the fluorescence of the N 3 phADP. At pH 6.7 one or two molecules of N 3 phADP bind with the tight binding sites of factor F 1 . This binding is accompanied by the manifold enhancement of the fluorescence of N 3 phADP. The results obtained indicate that the sites of factor F 1 that tightly bind nucleotides are immersed in the hydrophobic pocket of the protein molecule.