spacer

Entry M0284    3.5.5.8    thiocyanate hydrolase

Previous Step     Next Step

Step 05

The hydroxyl present on Cys133 activates a water molecule to act as a nucleophile towards the thio-acid intermediate.

GIF of Reaction Step M0284.stg05


Comment: The post translation modified hydroxyl group at Cys133 is thought to behave as a general base towards the incoming water molecule.
The enzyme is only active once hydroxylation has occurred at this position, and the existence of such a post translational modification has been hypothesized as a regulatory mechanism for enzyme activity [3].



Mechanisms

Proton Transfer
Bimolecular Nucleophilic Addition

Mechanism Components

Bond Order Change
Bond Formation
Bond Cleavage
Overall Reactant Used
Intermediate Formation

Amino acids involved in the reaction step.

Amino Acid Location of Function Activity Function
Ser132C Side Chain spectator Metal Ligand
Electrostatic Stabiliser
Activator
Ser132C Main Chain Amide spectator Metal Ligand
Electrostatic Stabiliser
Activator
Cys128C Side Chain spectator Metal Ligand
Electrostatic Stabiliser
Activator
Cso133C Main Chain Amide spectator Metal Ligand
Electrostatic Stabiliser
Activator
Cso133C Post-Translationally Modified Residue reactant Hydrogen Bond Acceptor
Proton Acceptor
Metal Ligand
Electrostatic Stabiliser
Tyr108C Side Chain spectator Hydrogen Bond Acceptor
Hydrogen Bond Donor
Csd131C Post-Translationally Modified Residue spectator Metal Ligand
Electrostatic Stabiliser
Activator

Metal Cofactors involved in Step 05

Metal Type Metal Identity Chain Activity Function
cobalt 3CO 301 C spectator Substrate Binding

Reactive Centre

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

View similar reactions in MACiE.


spacer
spacer