Enzymes are potent catalysts.
Compare the two reaction coordinate diagrams below and select the answer that correctly describes their relationship. An enzyme-catalyzed reaction was carried out with the substrate concentration initially 1,000 times greater than the K m for that substrate. X shows a fairly sharp decrease in its activity when the pH goes much lower than 6.4. Both water and glucose share an OH that can serve as a substrate for a reaction with the terminal phosphate of ATP catalyzed by hexokinase. Glucose, however, is about a million times more reactive as a substrate than water.