Using site-directed mutagenesis, you have created a mutant form of chymotrypsin that has alanine substituted for the usual serine at position 195. Which of the following effects would your expect to observe? a. No effect or slight increase in affinity for substrate coupled to a complete loss of enzyme activity. b. A decrease in the affinity for substrate coupled to a decrease in enzyme activity. c. An increase in the rate of peptide-bond cleavage due to an increase in the rate of acid-base catalysis. d. An increase in the rate of peptide-bond cleavage due to an increase in the rate of covalent catalysis. e. A complete loss of enzyme activity due to the inability to bind substrate