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Entry M0164    3.1.27.5    pancreatic ribonuclease

Previous Step

Step 02

His119 deprotonates water which attacks the cyclic phosphate intermediate in a nucleophilic substitution. The leaving alcohol group is reprotonated from His12.

GIF of Reaction Step M0164.stg02


Comment: Reaction proceeds through a pentavalent transition state.



Mechanisms

Proton Transfer
Bimolecular Nucleophilic Substitution

Mechanism Components

Overall Reactant Used
Bond Formation
Bond Cleavage
Intermediate Terminated
Overall Product Formed
Decyclisation
Hydrolysis
Enzyme Regenerated

Amino acids involved in the reaction step.

Amino Acid Location of Function Activity Function
His12 Side Chain reactant Hydrogen Bond Donor
Proton Donor
Lys41 Side Chain spectator Hydrogen Bond Donor
Electrostatic Stabiliser
His119 Side Chain reactant Hydrogen Bond Donor
Hydrogen Bond Acceptor
Proton Acceptor
Phe120 Main Chain Amide spectator Hydrogen Bond Donor
Electrostatic Stabiliser
Asp121 Side Chain spectator Hydrogen Bond Acceptor

Reactive Centre

Bonds Formed Bonds Cleaved Bonds Changed in Order Atom Types Involved
N-H
O-H
P-O
N-H
O-H
P-O
None
H
N
O
P

View similar reactions in MACiE.


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