$
    \newcommand{\avg}[1]{\langle #1 \rangle}
    \newcommand{\cc}[1]{[\mathrm{#1}]^{\mathrm{cell}}}
    \newcommand{\cgdp}{\mathrm{C \! \cdot \! GDP}}
    \newcommand{\cgtp}{\mathrm{C \! \cdot \! GTP}}
    \newcommand{\comb}[1]{{#1}^{\mathrm{comb}}}
    \newcommand{\conc}[1]{[\mathrm{#1}]}
    \newcommand{\conceq}[1]{[\mathrm{#1}]^{\mathrm{eq}}}
    \newcommand{\concss}[1]{[\mathrm{#1}]^{\mathrm{ss}}}
    \newcommand{\conctot}[1]{[\mathrm{#1}]_{\mathrm{tot}}}
    \newcommand{\cu}{\conc{U}}
    \newcommand{\dee}{\partial}
    \newcommand{\dgbind}{\Delta G_0^{\mathrm{bind}}}
    \newcommand{\dgdp}{\mathrm{D \! \cdot \! GDP}}
    \newcommand{\dgtp}{\mathrm{D \! \cdot \! GTP}}
    \newcommand{\dmu}{\Delta \mu}
    \newcommand{\dphi}{\Delta \Phi}
    \newcommand{\dplus}[1]{\mbox{#1}^{++}}
    \newcommand{\eq}[1]{{#1}^{\mathrm{eq}}}
    \newcommand{\fidl}{F^{\mathrm{idl}}}
    \newcommand{\idl}[1]{{#1}^{\mathrm{idl}}}
    \newcommand{\inn}[1]{{#1}_{\mathrm{in}}}
    \newcommand{\ka}{k_a}
    \newcommand{\kcat}{k_{\mathrm{cat}}}
    \newcommand{\kf}{k_f}
    \newcommand{\kfc}{k_{fc}}
    \newcommand{\kftot}{k_f^{\mathrm{tot}}}
    \newcommand{\kd}{K_{\mathrm{d}}}
    \newcommand{\kdt}{k_{\mathrm{dt}}}
    \newcommand{\kdtsol}{k^{\mathrm{sol}}_{\mathrm{dt}}}
    \newcommand{\kgtp}{K_{\mathrm{GTP}}}
    \newcommand{\kij}{k_{ij}}
    \newcommand{\kji}{k_{ji}}
    \newcommand{\kkeq}{K^{\mathrm{eq}}}
    \newcommand{\kmmon}{\kon^{\mathrm{ES}}} 
    \newcommand{\kmmoff}{\koff^{\mathrm{ES}}} 
    \newcommand{\kconf}{k_{\mathrm{conf}}}
    \newcommand{\konf}{k^{\mathrm{on}}_{\mathrm{F}}} 
    \newcommand{\koff}{k_{\mathrm{off}}}
    \newcommand{\kofff}{k^{\mathrm{off}}_{\mathrm{F}}} 
    \newcommand{\konu}{k^{\mathrm{on}}_{\mathrm{U}}} 
    \newcommand{\koffu}{k^{\mathrm{off}}_{\mathrm{U}}} 
    \newcommand{\kon}{k_{\mathrm{on}}}
    \newcommand{\kr}{k_r}
    \newcommand{\ks}{k_s}
    \newcommand{\ku}{k_u}
    \newcommand{\kuc}{k_{uc}}
    \newcommand{\kutot}{k_u^{\mathrm{tot}}}
    \newcommand{\ktd}{k_{\mathrm{td}}}
    \newcommand{\ktdsol}{k^{\mathrm{sol}}_{\mathrm{td}}}
    \newcommand{\minus}[1]{\mbox{#1}^{-}}
    \newcommand{\na}{N_A}
    \newcommand{\nai}{N_A^i}
    \newcommand{\nao}{N_A^o}
    \newcommand{\nb}{N_B}
    \newcommand{\nbi}{N_B^i}
    \newcommand{\nbo}{N_B^o}
    \newcommand{\nc}{N_{C}}
    \newcommand{\nl}{N_L}
    \newcommand{\nltot}{N_L^{\mathrm{tot}}}
    \newcommand{\nr}{N_R}
    \newcommand{\nrl}{N_{RL}}
    \newcommand{\nrtot}{N_R^{\mathrm{tot}}}
    \newcommand{\out}[1]{{#1}_{\mathrm{out}}}
    \newcommand{\plus}[1]{\mbox{#1}^{+}}
    \newcommand{\rall}{\mathbf{r}^N}
    \newcommand{\rn}[1]{\mathrm{r}^N_{#1}}
    \newcommand{\rdotc}{R \!\! \cdot \! C}
    \newcommand{\rstarc}{R^* \! \! \cdot \! C}
    \newcommand{\rstard}{R^* \! \! \cdot \! D}
    \newcommand{\rstarx}{R^* \! \! \cdot \! X}
    \newcommand{\ss}{\mathrm{SS}}
    \newcommand{\totsub}[1]{{#1}_{\mathrm{tot}}}
    \newcommand{\totsup}[1]{{#1}^{\mathrm{tot}}}
    \newcommand{\ztot}{Z^{\mathrm{tot}}}
% Rate notation: o = 1; w = two; r = three; f = four
    \newcommand{\aow}{\alpha_{f}}
    \newcommand{\awo}{\alpha_{u}}
    \newcommand{\kow}{\kf}  % {\kf(12)}
    \newcommand{\kwo}{\ku}  % {\ku(21)}
    \newcommand{\kor}{\conc{C} \, \konu}  %  \konu(13)}
    \newcommand{\kwf}{\conc{C} \, \konf}  %  \konf(24)}
    \newcommand{\kro}{\koffu}  %  {\koffu(31)}
    \newcommand{\kfw}{\kofff}  %  {\kofff(42)}
    \newcommand{\krf}{\kfc}  % {\kfc(34)}
    \newcommand{\kfr}{\kuc}  % {\kuc(43)}
    \newcommand{\denom}{ \krf \, \kfw + \kro \, \kfw + \kro \, \kfr }
    $