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Entry M0196    5.5.1.6    chalcone isomerase

Step 01

The chalcone substrate undergoes an intramolecular nucleophilic addition, and deprotonates a water molecule to generate the flavanone product.

GIF of Reaction Step M0196.stg01


Comment: The cyclisation reaction proceeds through a transition state in which charge delocalisation results in the transient protonation of the transition state enolate by the water molecule hydrogen bonded to Tyr106 [1,2].



Mechanisms

Intramolecular Nucleophilic Addition
Proton Transfer

Mechanism Components

Overall Reactant Used
Bond Formation
Bond Cleavage
Bond Order Change
Overall Product Formed

Amino acids involved in the reaction step.

Amino Acid Location of Function Activity Function
Tyr106 Side Chain spectator Activator
Hydrogen Bond Donor
Thr48 Side Chain spectator Hydrogen Bond Donor
Electrostatic Stabiliser

Reactive Centre

Bonds Formed Bonds Cleaved Bonds Changed in Order Atom Types Involved
C-H
C-O
O-H
The C-C bond changes from a double to single bond
C
H
O

View similar reactions in MACiE.


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