Week 10 Key
- Given reactant and products, write and explain mechanism.
- Key catalytic mechanism is covalent catalysis:
- Lysine N attacks keto group of Fructose to form a Schiff
- The positive charge on the N of the Schiff base provides
an electron sink which helps to stabilize the carbanion formed
during bond breakage (good resonance structures).
- Catalysis is aided by a general base abstraction of a hydroxyl
proton to ease the formation of an aldehydic oxygen on the Ga-3-P
- The Schiff base is hydrolysed by water to regenerate the
enzyme and release DHAP.
- Draw a "Kinetic Mechanism Diagram" for this reaction.
- Correlate the kinetic and chemical mechanisms.
- Note that order of addition/release is consistant with catlytic mechanism.
©R A Paselk
Last modified 25 March 2011