Enzymatic Activity

Question 1

Vmax

Answer 1

the maximum speed at which an enzyme can work (change in substrate concentration wouldn’t matter)

Question 2

things to remember about enzyme activity…

Answer 2

1. assume steady state (formation of [ES] is equal to the loss of [ES])
2. Michaelis-menten equation
3. Catalytic efficiency

Question 3

michaelis-menten equation (draw)

Answer 3

draw out

Question 4

catalytic efficiency

Answer 4

Kcat / Km

Question 5

Lineweaver-Burke plot (LB)

Answer 5

based on the MM equation

Question 6

competitive inhibitor

Answer 6

competes for space on the enzyme ([EI])

changes slope; does not change V_max if substrate concentrations are high

Question 7

uncompetitive inhibitor

Answer 7

binds to enzyme-substrate to form [ESI] and does not react

changes the Vmax (y-intercept), but does not change the slope , Km/Vmax

Question 8

non-competitive (mixed) inhibitor

Answer 8

can bind to free enzymes [EI] or substrate-complex [ESI]

graph shows change in slope and y-intercept

Question 9

cooperativity

Answer 9

active site saturation does not increase linearly with an increase in substrate concentration; a small increase in [S] will increase the rate at which something binds (S curve)

Question 10

hemoglobin

Answer 10

displays positive cooperative binding (binds 4 O2 molecules)

Question 11

myoglobin

Answer 11

displays non-cooperative binding because it can only bind with 1 O2 molecule

Question 12

allosteric site

Answer 12

a site away from the active site

Question 13

homotropic inhibitor

Answer 13

substrate and inhibitor are the same molecule

Question 14

receptors/ion channel

Answer 14

insulin binds to insulin receptor protein in a lipid bilayer, leads to a cascade of signals