BIOC2000 Lecture Notes - Lecture 28: Oxyanion Hole, Conjugate Acid, Deprotonation
Monday, 14 May, 2018
Gilam Lec
How different AA contribute to catalysis (role)
-Acid base mechanism of electron pushing (DHAP Intermediate not very stable
breaksdown to DA3P residue taking proton
-conjugate acid donating proton
-Electrostatic catalysis
-promote movement of electrons (lys positive)
-improve efficiency of reaction
-help orient
-deprotonation of substrates
-stabilise TS
-interact with side chains and change their property by pka
-covalent bond alternative pathway for product
-2 intermediates, some residues leave after 1 intermediate reach
-oxyanion hole form bond
-cleave bond with water hydrolysis serine pick up p from his to cleave bond
-serine and histadin reform
-aromatic group binds to hydrophobic pocket
-ser no h gp
-existing as conjugate base form is better change p off better nucleophile in water
-form covalent bonding to keep hold s and intermediate without dissociate and interact
with water
-Quantify enzymen and see how efficient they are
-enzymes produce product in high yield
-how
-rate increase with s conc
-enzymes are saturable
-time is kinetic
1
Document Summary
Acid base mechanism of electron pushing (dhap intermediate not very stable breaksdown to da3p residue taking proton. Interact with side chains and change their property by pka. 2 intermediates, some residues leave after 1 intermediate reach. Cleave bond with water hydrolysis serine pick up p from his to cleave bond. Existing as conjugate base form is better change p off better nucleophile in water. Form covalent bonding to keep hold s and intermediate without dissociate and interact with water. Quantify enzymen and see how ef cient they are. If time change to s conc, rectangular hyperbola. Enzymes working as hard as they can already with substrate,saturation. Rate decrease with x s conc s depleted p build up. When measure initial rate where rate is maximal, we can neglect k2. Vo is initial rate p conc/time = k2 x [es] Es con constant while s doen p up. Break of es / build up of es.
