  Bazhin has analyzed ATP coupling in terms of quasiequilibrium states where
fast reactions have reached an approximate steady state while slow reactions
have not yet reached equilibrium. After an expository introduction to the
relevant aspects of reaction network theory, we review his work and explain the
role of emergent conserved quantities in coupling. These are quantities, left
unchanged by fast reactions, whose conservation forces exergonic processes such
as ATP hydrolysis to drive desired endergonic processes.
