24. How enzymes work Draw and label a reaction coordinate diagram for an uncatalyzed reaction, S P, and the same reaction catalyzed by an enzyme, E. 25. How enzymes work The difference in (standard) free energy content, G”, between substrate S and product P may vary considerably among different reactions. What is the significance of these differences? 26. How enzymes work For a reaction that can take place with or without catalysis by an enzyme, what would be the effect of the enzyme on the: (a) standard free energy change of the reaction? (b) activation energy of the reaction? (c) initial velocity of the reaction? (d) equilibrium constant of the reaction? 27. How enzymes work Sometimes the difference in (standard) free-energy content, G”, between a substrate S and a product P is very large, yet the rate of chemical conversion, S P, is quite slow. Why?