Hi, I don't understand the part in bold about the Michaelis-Menton kinetic model of catalysis, could someone please try and explain it?
E = enzyme, S = substrate, P = product
Step 1) E + S -> ES [fast, reversible]
Step 2) ES -> E + P [slow, rate-determining] • The substrate binds to the enzyme at the active site to form an enzyme-substrate complex (ES). ES then reacts to form the product in the slow rate determining step. •WhenEa =0 and steric factor A=1 reactions are diffusion controlled - this is as fast as a reaction can go. For 2 molecules of the same size diffn control gives rates which approach the encounter frequency of 7 x 109 s-1 M-1.
• Many enzyme systems approach this rate.
eg. acetylcholinesterase k =1.6 x 109 s-1 M-1