Kinetic analysis of proton translocation catalyzed by F₀F₁ ATPase

Abstract

Kinetic analysis of both proton translocating and steady-state ATP hydrolytic activities catalyzed by F,F, ATPase in submitochondrial particles were carried out over an ATP concentration range of I-2000 PM. The results were examined in relation to the prediction based on the alternate binding change model proposed by Gresser et al. ((1982) J. Biol. Chem. 257, 1203&12038] in which energy transduction occurs only at the tri-site catalytic cycle. The present results essentially contrast with the model and rather indicate that if the alternate binding mechanism holds for the ATP hydrolytic reaction, the proton translocation should be coupled to at least both bi-site and tri-site cycles.

Catalytic Activity of the α3β3γ Complex of F1-ATPase without Noncatalytic Nucleotide Binding Site

“…F 1 -ATPase exhibits negative cooperativity characterized with two or three apparent K m values which are 1-30 M, 100 -300 M, and above 400 M (20 -24). This apparent negative cooperativity is observed also for the membrane-bound enzyme (25) and proton translocation (26). Slow binding of ATP to noncatalytic sites can explain apparent negative cooperativity at relatively high concentration of ATP represented by the highest K m value (4).…”

A rotary molecular motor that can work at near 100% efficiency

“…Bi-site hydrolysis in ATP synthase pumps protons (Muneyuki & Hirata 1988). bacterial origin used to demonstrate the g rotation was suspended in solution without attaching actin.…”

Cross-linking of Two β Subunits in the Closed Conformation in F1-ATPase

“…This reaction is accelerated by chase-addition of an excess amount of ATP (chase-promotion) (8 -10). As a whole, ATP hydrolysis reaction by F 1 -ATPase usually exhibits negative cooperativity as a function of ATP concentration (11)(12)(13)(14)(15)(16). These and other features had been unified into the binding change mechanism by Boyer (3).…”