Lecture 2 Flashcards
What is the equation for the association rate?
Association rate = k1 [P] [L]
What is the diffusion limit?
10^9 M/s
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
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.
When were the michealis menten experiments performed?
1913
What is the underlying principle of michealis menton kinetics?
E + S -> ES -> EP and v= Vmax [S] / Km +[S]
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
What is the range of typical km values for enzymes?
10-1 to 10-7 M
What is the criteria for an efficient enzyme?
Small Km
Large Vmax
K2»_space;k1
Give an example of an efficient enzyme
Acetyl cholinesterade
Give an example of an inefficient enzyme
Complement proteases such as MASP-2 as substrate specificity is more important than killing
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
What is the equation for Kd?
Kd=[P][L] / [PL]
