Lecture 13: Kinetics

Question 1

Competitive inhibition effects on Vmax and Km

Answer 1

Vmax stays the same

Km is increased

Question 2

Uncompetitive inhibition effects on Vmax and Km

Answer 2

Vmax is reduced

Km is reduced

Question 3

Noncompetitive inhibition effects on Vmax and Km

Answer 3

Vmax is reduced

Km stays the same

Question 4

Km definition

Answer 4

[S] where reaction rate is half maximal

Half of the active sites are full

Question 5

Vmax definition

Answer 5

Maximum rate possible for a given concentration of enzyme

Question 6

Kcat definition

Answer 6

Turnover number

Number of substrate molecules converted per active site per time

Question 7

Ks definition

Answer 7

A dissociation constant for substrate binding

Question 8

Kcat/Km

Answer 8

Specificity constant

Measure of enzyme performance by predicting the fate of E S

Question 9

Michaelis-Menten equation

Answer 9

V0 = Vmax*[S] / Km + [S]

Question 10

V0 when [S] &laquo_space;Km

Answer 10

V0 = (Vmax / Km)*[S]

Question 11

V0 when [S] = Km

Answer 11

V0 = Vmax / 2

Question 12

V0 when [S]&raquo_space; Km

Answer 12

V0 = Vmax

Question 13

Kcat of a good enzyme would be

Answer 13

Kcat&raquo_space; K-1

Kcat/Km =~ K1

Question 14

Kcat of a bad enzyme would be

Answer 14

Kcat &laquo_space;K-1

Kcat/Km =~ 1/Km

Question 15

Multiple binding site enzymes can follow Michaelis-Menten kinetics, as long as they are

Answer 15

Noncooperative

Question 16

Y and X intercepts and slope of double reciprocal (Lineweaver-Burk) plot

Answer 16

Y intercept = 1/Vmax
X intercept = -1/Km
Slope = Km/Vmax

Question 17

Group specific inhibitors do what, specificity

Answer 17

Target specific amino acid

Low specificity for active site

Question 18

Substrate analog inhibitors do what, specificity

Answer 18

Substrate mimic, modify enzyme

High specificity for active site

Question 19

Suicide inhibitors do what, specificity

Answer 19

Substrate mimic, unable to form products

Very high specificity for active site