ENZYMES: Inhibition and Regulation

Question 1

A type of inhibitor that binds directly only to free E (enzyme); reducing enzyme concentration available for substrate binding.

Answer 1

Competitive Inhibitor

Question 2

A type of inhibitor that interacts with either an enzyme of an enzyme-substrate complex, that cannot be reversed by increasing substrate concentration.

Answer 2

Non-competitive Inhibitor

Question 3

This type of inhibitor is similar to Non-competitive Inhibitor, which its binding affects the binding of the substrate.

Answer 3

Mixed Non-competitive Inhibitor

Question 4

This type of inhibitor binds directly to the enzyme-substrate complex; distorts the active site, affecting catalytic function but not its substrate binding. It is significant only in multi-substrate enzymes.

Answer 4

Uncompetitive Inhibitors

Question 5

This type of inhibitor binds directly to the enzyme-substrate complex; distorts the active site, affecting catalytic function but not its substrate binding. It is significant only in multi-substrate enzymes.

Answer 5

Uncompetitive Inhibitors

Question 6

An end product inhibits key enzymes which forms the intermediates.

Answer 6

Feedback Inhibition

Question 7

An enzyme which initiates the reaction for the synthesis of cytidine triphosphate (CTP).

Answer 7

Aspartate transcarbamoylase (ATCase)

Question 8

What inhibits ATCase?

Answer 8

Cytidine triphosphate (CTP)

Question 9

A process in which allosteric regulators bind to regulatory sites to regulate catalytic activity.

Answer 9

Allosteric Regulation

Question 10

Conformational transitions that affect substrate binding.

Answer 10

Taut (T) Conformation and Relaxed (R) Conformation.

Question 11

The relationship of T and R conformations to affinity

Answer 11

T confirmation means lower affinity; R conformation means higher affinity.

Question 12

In the absence of a substrate, what exists?

Answer 12

An equilibrium between T and R conformation

Question 13

Inhibitors that favor T conformation

Answer 13

Allosteric inhibitors

Question 14

This favors to R conformation

Answer 14

Activators

Question 15

Sequential activation of the sub-units upon binding of a substrate to one of the catalytic sites of a multi-domain enzyme.

Answer 15

Sequential Model

Question 16

Introduction of a group to the enzyme either activate or deactivate the enzyme.

Answer 16

Covalent Modification

Question 17

Processes involved in Covalent Modification

Answer 17

Phosphorylation and Methylation

Question 18

The inactive precursor of enzymes

Answer 18

Zymogen

Question 19

Components of Zymogen

Answer 19

Pepsinogen, Trypsinogen, and Chymotrypsinogen

Question 20

Glucose transporters

Answer 20

GLUT1–4

Question 21

GLUT1

Answer 21

Erythrocyte

Question 22

GLUT2

Answer 22

Liver

Question 23

GLUT3

Answer 23

Brain

Question 24

GLUT4

Answer 24

Muscle

Question 25

The process where substrate binds to repressor allowing polymerase to transcribe mRNA

Answer 25

Genetic Induction

Question 26

Similar structure but has a lower energy requirement when compared to a substrate.

Answer 26

Transition State Analog

Question 27

DANA

Answer 27

2 - deoxy - 2,3 - dehydro-N-acetylneuraminic acid

Question 28

It is essential for viral glycoprotein or gkycosaminoglycan synthesis and is a substrate for neuraminidase.

Answer 28

DANA