Enzyme Kinetics

Question 1

Velocity

Answer 1

Rate of formation of product per unit of time

Velocity of all enzymes is dependent on the concentration of of substrate

Question 2

Velocity =V

Answer 2

Disappearance of S or the rate of disappearance of P

V= -(d[S]/dt) Or (d[P]/dt)

Question 3

Small Km

Answer 3

High affinity of enzyme for substrate

Lower Km: [E] more efficient at low [S]

Question 4

Large Km

Answer 4

Low affinity of enzyme for the substrate

Higher Km : [E] less effective

Question 5

k cat (Turnover number)

Answer 5

How many substrate molecules can one enzyme molecule convert per second

k3 = k cat = Vmax / [Et]

[Et] : enzyme concentration

Question 6

Catalytic efficiency

Answer 6

Measures how efficiently the enzyme converts substrate to product and describes preference for substrate

k cat / Km

Question 7

Km

Answer 7

Km = ([E][S])/([ES])

   =       ([E][S])/([Product])

Question 8

V max

Answer 8

Vmax= k cat • [Et]

[Et] = enzyme concentration

Question 9

Ping-pong mechanism

Answer 9

One S binds and is made into two pieces one is a P and the other is still a S

The remaining S is combined with S’ and turned into P’

Two different products are made P & P’