Conversion of substrates S1 and S2 to products P1 and P2, respectively, S1 r1 P1, S2 r2 P2 is catalyzed by the same enzyme as per the reaction mechanism (1) E + S1 k ES1 (2) ES1 EP1, Kr1 (3) EP1 E + P1, KP1 (4) E + S2 ES2, KS2 (5) ES2 EP2, Kr2 (6) EP2 k E + P2 KP1 and KS2 are dissociation equilibrium coefficients and Kr1 and Kr2 are equilibrium coefficients for surface reaction steps. The irreversible steps, steps 1 and 6, are the rate determining steps (RDSs) for the two reactions. Pseudo-equilibrium relations can be used for all other steps. Obtain expressions for r1 and r2 and comment on whether each of the four species promotes, inhibits or does not affect each reaction.