PRELIM 04 - Enzyme Inhibition and Regulation

Question 1

Binds directly on the active site (Types of inhibitors)

Answer 1

Competitive inhibitors

Question 2

Binds to allosteric sites (Types of inhibitors)

Answer 2

Non-competitive inhibitors

Question 3

Similar to noncompetitive inhibitors; binding of inhibitor affects binding of substrate (Types of inhibitors)

Answer 3

Mixed non-competitive inhibitors

Question 4

Binds directly to the enzyme-substrate complex, but not to free the enzyme; distorts the active site (Types of inhibitors)

Answer 4

Uncompetitive inhibitors

Question 5

Applicable in multi-step pathways; an end product inhibits key enzymes which form the intermediates (Forms of enzyme regulation)

Answer 5

Feedback inhibition

Question 6

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

Answer 6

Aspartate transcarbamyolase (ATCase)

Question 7

Allosteric regulators binds to regulatory sites to regulate catalytic activity (Forms of enzyme regulation)

Answer 7

Allosteric regulation

Question 8

__________ is an activator of ATCase

Answer 8

Adenosine triphosphate (ATP)

Question 9

__________ is an inhibitor of ATCase

Answer 9

Cytidine triphosphate (CTP)

Question 10

Conformational transitions affect substrate binding

Answer 10

Taut (T) and relaxed (R) conformations

Question 11

Model that presents that the presence of substrate affects the equilibrium towards R conformation

Answer 11

Concerted model

Question 12

__________ bind to favor T conformation

Answer 12

Allosteric inhibitors

Question 13

__________ bind to favor R conformation

Answer 13

Activators

Question 14

Model that presents the sequential activation of the subunits upon binding of a substrate to one of the catalytic sites of a multi-domain enzyme

Answer 14

Sequential model

Question 15

Involves the introduction of a group to the enzyme either to activate or deactivate the enzyme (Forms of enzyme regulation)

Answer 15

Covalent modification

Question 16

2 examples of covalent modification

Answer 16

Phosphorylation, Methylation

Question 17

Is an inactive precursor of enzymes (Forms of enzyme regulation)

Answer 17

Zymogen

Question 18

3 examples of zymogen

Answer 18

Pepsinogen, Trypsinogen, Chymotrypsinogen

Question 19

Enzymes in different cell types may have different isoforms (Forms of enzyme regulation)

Answer 19

Isoenzyme forms

Question 20

Meaning of GLUT; is an example of isoenzyme form

Answer 20

Glucose transporters

Question 21

GLUT1 is present in __________

Answer 21

Erythrocytes

Question 22

GLUT2 is present in the __________

Answer 22

Liver

Question 23

GLUT3 is present in the __________

Answer 23

Brain

Question 24

GLUT 4 is present in the __________

Answer 24

Muscle

Question 25

Ranking of GLUT transport from highest to lowest affinity

Answer 25

GLUT 3, GLUT 4, GLUT 2, GLUT 1

Question 26

Refers to the increase in the amount of enzyme protein as a result of some stimulus (Forms of enzyme regulation)

Answer 26

Genetic induction

Question 27

Have the same structure as the substrate in the enzyme-substrate complex

Answer 27

Transition state analog

Question 28

Is a substrate for neuraminidase; essential for viral glycoprotein; glycosaminoglycan synthesis

Answer 28

2-deoxy-2,3-dehydro-N-acetyl neuraminic acid (DANA)