Lecture 2 Flashcards Preview

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Flashcards in Lecture 2 Deck (13):
1

What is the equation for the association rate?

Association rate = k1 [P] [L]

2

What is the diffusion limit?

10^9 M/s

3

Outline surface resonance and what it would be used to measure

Surface resonance is a technique to kinetically measure the Kd.
It detects changes in the refractive index in the immediate vicinity of the surface layer of a sensor chip. This change in refractive index is dependent on the mass of material on the surface chip

4

What is stopped flow?

A kinetic method to measure the Kd, in which solutions are forced from syringes into the mixing chamber. After a short period of flow they are stopped rapidly when the observation cell is filled. Therefore we can work out the rate of reaction from the fluorescence data.

5

When were the michealis menten experiments performed?

1913

6

What is the underlying principle of michealis menton kinetics?

E + S -> ES -> EP and v= Vmax [S] / Km +[S]

7

What are the three assumptions made in steady state kinetics?

[ES] is constant
initial substrate concentration is much much greater than enzyme concnetration
The back reaction can be ignored as initial product = 0

8

What is the range of typical km values for enzymes?

10-1 to 10-7 M

9

What is the criteria for an efficient enzyme?

Small Km
Large Vmax
K2 >>k1

10

Give an example of an efficient enzyme

Acetyl cholinesterade

11

Give an example of an inefficient enzyme

Complement proteases such as MASP-2 as substrate specificity is more important than killing

12

What mechanisms can enzymes work by?

Strain towards transition state
Local high concentration
Orientation of reacting groups
Provide chemical groups
Covalent intermediates
Charge stabilisation
Metal ions
Co-enzymes

13

What is the equation for Kd?

Kd=[P][L] / [PL]