Enzyme rate

Question 1

Define what Km and Kcat is, ow can these be used to show how productive an enzyme is

Answer 1

Km = [s] at 1/2 Vmax. Measure of the affinity to substrate, lower Km = higher affinity
Kcat = is the amount of substrate produced per enzyme per unit time

Kcat/Km = enzyme efficeny higher number = more efficent
- wants low km
- high Kcat

Question 2

What is Vmax and V0

Answer 2

V0 is the inital enzyme activity
Vmax is the maximum production given a fixed quanity of enzymes

Question 3

What is an enzyme progress curve

Answer 3

A plot of the product over time. Linear until slows as the [S] decreases over time

Question 4

How can V be calculated at any timepoint

Answer 4

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

Question 4

What is a michaelis menten plot

Answer 4

a plot of the V over [s], with a fixed amount of enzyme
Plot is linnear as [s] increases until all enzyme active sites are filled then tapers off rate no longer dependant on substrate - Forms a RECTANGULAR HYPERBOLA

Question 5

What assumptions must be made for the michaelis menten plot to be true

Answer 5

• products dont turn back into substrate
• conc of [S] > [E]
• There is always constnat [ES]

Question 6

What does the lineweaver byck equasion show

Answer 6

1/v over 1/[s], y-int = 1/Vmax, X-int = -1/Km

slope = km/vmax

Question 7

Why do we measure enzyme factors

Answer 7

In cells it is more common to reguklate the [s] than the [e],

Question 8

What is K2 and Kd

Answer 8

K2 = the rate of product forming, normally RDS
Kd = dissociation constant = K-1/K1 = Km

Question 9

When is enzyme concentration proportional to reaction velocity

Answer 9

When there is an exces of substrate