Open AccessUnifying concept for the coupling between ion pumping and ATP hydrolysis or synthesis.
Author(s) -
Gordon G. Hammes
Publication year - 1982
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.79.22.6881
Subject(s) - chemistry , atp hydrolysis , enzyme , atpase , coupling (piping) , conformational change , catalysis , ion , hydrolysis , biophysics , mechanism (biology) , enzyme catalysis , stereochemistry , combinatorial chemistry , biochemistry , organic chemistry , materials science , biology , physics , metallurgy , quantum mechanics
A mechanism is proposed for the coupling between ion transport and enzyme catalysis. The basic concept is that enzymes associated with transport exist in two possible conformations. Each conformation has the potential of catalyzing the enzymatic reaction, and pumping is associated with the conversion of one conformational form to the other. The conformational transition is triggered by the kinetic blockage of specific mechanistic steps for each conformation. Such blockages can cause a cycling between the two conformations concomitant with catalysis. This mechanistic concept is consistent with a variety of results obtained with the Na+,K+-ATPase, the Ca2+,Mg2+-ATPase, and ATP synthesizing enzymes (coupling factors).