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Entry M0164    3.1.27.5    pancreatic ribonuclease

Next Step

Step 01

His12 deprotonates the alcohol of the 5' RNA ribose, which initiates an intramolecular nucleophilic substitution on the phosphate bond of the RNA molecule. The leaving alcohol group is reprotonated from His119.

GIF of Reaction Step M0164.stg01


Comment: Reaction proceeds through a pentavalent transition state.



Mechanisms

Proton Transfer
Intramolecular Nucleophilic Substitution

Mechanism Components

Overall Reactant Used
Bond Formation
Bond Cleavage
Intermediate Formation
Overall Product Formed
Cyclisation

Amino acids involved in the reaction step.

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

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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