1. All of the following are correct statements about enzyme regulation EXCEPT: a. Enzymes can be inhibited by the products they produce. b. Enzymes can be inactivated by the addition of a functional group. c. Coenzyme and substrate availability can regulate enzyme reaction rate. d. The reaction rate slows as equilibrium is approached. e. The activity of an enzyme is covalently affected by allosteric regulators. ANSWER: e 2. All of the following are examples of a zymogen and its activating protease EXCEPT: a. chymotrypsinogen and chymotrypsin. b. procarboxypeptidase and elastase. c. proelastase and elastase. d. pepsinogen and pepsin. e. trypsinogen and trypsin. ANSWER: b 3. Proinsulin is converted into insulin by: a. proteolytic excision of a specific peptide. b. allosteric binding of glucose. c. phosphorylation to the active form. d. removal of phosphate by converter enzymes. e. none of the above. ANSWER: a

1-For the first one, the statement which is not correct about enzyme regulation is the statement e which is The activity of an enzyme is covalently affected by allosteric regulators

2-The example which does not have a zymogen and activating protease is example b which is procarboxypeptidase and elastase.

3-The process by which proinsulin is converted into insulin is by method a which is proteolytic excision of a specific peptide.

Explanation:

1-All the other statements are correct as indicated below:

a-Enzymes can be inhibited by the products they produce. This is true because the rate of production is reduced in cases of some products. this indicates that the enzymes are not being able to further act.

b-Enzymes can be inactivated by the addition of a functional group. This is true because enzymes can be activated and inactivated manually.

c-Coenzyme and substrate availability can regulate enzyme reaction rate. This is true because lack or shortage conenzyme or substrate can reduce the reaction rate due to lack of availability of required components.

d-The reaction rate slows as equilibrium is approached. This is true as the reaction reaches equilbrium less products are converted back to reactants and less reactants are converted into products.

2-

Similarly all the other examples for 2 have either an activating protease or zymogen except procarboxypeptidase and elastase.

3-

The proinsulin has a specific peptide which is excised thus only option a is correct.