We can extend our discussion by considering how requiring the motor to perform work against an opposing force affects its rotation. The net directionality of the network is modified such that 𝑟 𝑤 = 𝑟 0 𝑒 w RT, where 𝑟 𝑤 is the directionality of the motor under load and ∆w is the work done over one cycle of the network. 13g From here we can recognize that 𝑒 -w 𝑚𝑎𝑥 RT = 𝑟 0 , where w 𝑚𝑎𝑥 is the maximum work per cycle. 13g Given that r0 (eq. 3a) depends on the properties of the network (i.e., rate constants, ∆G rxn ) and the conditions of operation (i.e., concentrations), the same is true of w 𝑚𝑎𝑥 , but the exact form of this dependence is nonintuitive. The discussion can be simplified by considering the maximum value of r0 that can be achieved if motor 6 is perfectly optimized (see ESI): 𝑒 -w 𝑚𝑎𝑥 RT = 𝑒 -∆G rxn RT ሾNEt 3 ሿሾFmocClሿ ሾNEt 3 HClሿሾCO 2 ሿሾ𝟓ሿ . 47 Thus, the maximum work is not limited by ∆G rxn . Finally, if the work done over one reaction cycle takes place over a distance l, we see that if F > ∆w 𝑚𝑎𝑥 𝑙 , the direction of motor is reversedas expected, the applied force causes the motor to run backwards.