Regulations of enzymatic activity - Inhibition Kinetics

Question 1

In Lineweaver-Burk Plot: y-intercept is

Answer 1

1/ Vmax (Vmax)

Question 2

In Lineweaver-Burk Plot: x-intercept is

Answer 2

-1/Km (Km)

Question 3

In Lineweaver-Burk Plot: Slope =

Answer 3

Km/Vmax

Question 4

What is a Cofactor

Answer 4

prosthetic group need to ‘activate’ the apoenzyme

Question 5

What is a Apoenzyme

Answer 5

protein portion of enzyme almost ready to work

Question 6

Equilibrium shifts to the left if

Answer 6

product starts to build up

Question 7

Positive allosterism

Answer 7

activates the enzyme

Question 8

Negative allosterism

Answer 8

deactivates the enzyme

Question 9

Feedback inhibition

Answer 9

a type of allosteric effect where the product acts as the effector molecules

Question 10

Zymogens

Answer 10

Inactive forms of an enzyme

Question 11

Inhibitors

Answer 11

release materials that block off the active site of the enzyme (may be reversible)

Question 12

Irreversible Inhibitors

Answer 12

Forms covalent or very strong bonds

Question 13

Reversible Inhibitors

Answer 13

Forms weak noncovalent bonds (only inactive when inhibitor is present)

Question 14

Competitive Inhibitor

Answer 14

+ Competes with substrate (binds to active site)

+ Vmax not affected

+ Km increases

Question 15

Uncompetitive Inhibitor

Answer 15

+ Binds to ES complex

+ Reduces Vmax and Km

Question 16

Noncompetitive Inhibitor

Answer 16

+ Binds to separate site

+ Vmax reduced

+ Km unaffected

Question 17

Competitive Equations

Answer 17

+ Ki = [E][I]/[EI]

+ low Ki = strong inhibition

+ More EI formed less enzymes available

Question 18

Uncompetitive Equation

Answer 18

+ Ki = [ES][I]/[ESI]

+ ESI will always be present -> Vmax will be lowered

+ Depletes ES

Question 19

Noncompetitive Equation

Answer 19

Ki = [E][I]/[EI] = [ES][I]/[ESI]