Enzyme activity may be regulated by several means. What is the mode of regulation in each of the following examples?
A) allosteric regulation or feedback inhibition
B) substrate-level regulation
C) inhibition
D) proteolytic cleavage
1) When glucose is converted to glucose-6-phosphate by hexokinase, the accumulation of glucose-6-phosphate inhibits the reaction.
2) A foreign substance is added to the reaction in part a above. This substance binds to hexokinase and prevents its ability to catalyze the reaction. E) covalent modification
3) An inactive form of an enzyme becomes active after being phosphorylated.
4) Pepsinogen becomes pepsin after being released into the lumen of the stomach.
5) In a series of enzymatic reactions, it is found that the product of the last reaction inhibits the first enzyme in the series of reactions.
Answers: 1) B 2) C 3) E 4) D 5) A
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