Alternating site sequence for oxidative phosphorylation suggested by measurement of substrate binding patterns and exchange reaction inhibitions

Journal Article · Mon Apr 25 00:00:00 EDT 1977 · J. Biol. Chem.; (United States)

OSTI ID:7311006

Kayalar, C; Rosing, J; Boyer, P D

Catalysis by beef heart submitochondrial particles of the medium P/sub i/ reversible HOH, P/sub i/ reversible ATP, and the ATP reversible HOH exchanges is strongly inhibited while the ATPase and intermediate P/sub i/ reversible HOH exchange are accelerated when medium ADP is removed by pyruvate kinase action. Arsenate readily blocks completely the P/sub i/ reversible ATP and medium P/sub i/ reversible HOH exchange reactions, but not the ATP reversible HOH exchange reaction. The residual ATP reversible HOH exchange in presence of arsenate is inhibited by 2,4-dinitrophenol. These results and other data are explained by an alternating site model for oxidative phosphorylation. In this model during net oxidative phosphorylation ATP is formed at one site but is transitorily tightly bound and not released until ADP and P/sub i/ bind at a second site and the membrane ATPase complex is energized. Under conditions of net ATP hydrolysis, ATP binding at one site is accompanied by hydrolysis of the transitorily tightly bound ATP at a second site. Attractive features are only one site of input for conformational energization of the membrane ATPase, a single conformational transition that accounts for both the promotion of ADP and P/sub i/ binding in a competent mode and the release of tightly bound ATP, and a symmetry of catalytic sites.

• Research Organization: Univ. of California, Los Angeles
• OSTI ID: 7311006
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 252:8; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ADP
ATP
ATP-ASE
BIOLOGICAL MODELS
BODY
CARDIOVASCULAR SYSTEM
CATALYSIS
CELL CONSTITUENTS
CHEMICAL BONDS
CHEMICAL REACTIONS
DECOMPOSITION
ENZYMES
ESTERASES
HEART
HYDROGEN COMPOUNDS
HYDROLASES
HYDROLYSIS
LYSIS
METABOLISM
MITOCHONDRIA
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
OXYGEN COMPOUNDS
PHOSPHATASES
PHOSPHORYLATION
PHOSPHOTRANSFERASES
SOLVOLYSIS
TRANSFERASES
WATER