Subunit interaction during catalysis: alternating site cooperativity in photophosphorylation shown by substrate modulation of (/sup 18/O)ATP species formation

Journal Article · Wed Aug 01 00:00:00 EDT 1979 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.76.8.3646· OSTI ID:5374478

Hackney, D D; Rosen, G; Boyer, P D

Pronounced substrate modulation of incorporation of water oxygen into ATP formed by photophosphorylation is observed, as measured by /sup 31/P NMR analysis of products formed from ADP and highly /sup 18/O-labeled P/sub i/. A marked increase occurs in oxygen exchange per ATP formed as ADP or P/sub i/ concentration is decreased. This is explainable by the binding-change mechanism for ATP synthesis, in which the energy linked release of ATP from one site requires the binding of ADP and P/sub i/ at an alternate site. Analysis of the distribution of /sup 18/O-labeled species arising from the ATP formed eliminates explanations for substrate modulation based on preexisting or induced enzyme heterogeneity. Furthermore, the results, together with other related findings, make participation of control sites unlikely. The occurrence of alternating site catalysis cooperativity in ATP synthesis by chloroplasts thus appears to be reasonably well established.

• Research Organization: Univ. of California, Los Angeles, CA (United States)
• DOE Contract Number: EY-76-S-03-0034
• OSTI ID: 5374478
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 76:8
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ATP
BIOSYNTHESIS
OXYGEN 18
TRACER TECHNIQUES
PHOSPHORYLATION
PHOTOCHEMICAL REACTIONS
BIOCHEMICAL REACTION KINETICS
CATALYSIS
CHLOROPLASTS
LABELLED COMPOUNDS
NUCLEAR MAGNETIC RESONANCE
PHOSPHORUS
PHOSPHORUS 31
CELL CONSTITUENTS
CHEMICAL REACTIONS
ELEMENTS
EVEN-EVEN NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
MAGNETIC RESONANCE
NONMETALS
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
OXYGEN ISOTOPES
PHOSPHORUS ISOTOPES
REACTION KINETICS
RESONANCE
STABLE ISOTOPES
SYNTHESIS
550201* - Biochemistry- Tracer Techniques