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Entry M0234    6.3.5.2    GMP synthase (glutamine-hydrolysing)

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Step 02

His181 deprotonates Cys86, activating it for a nucleophilic attack upon L-glutamine, forming an enzyme-substrate covalent bond.

GIF of Reaction Step M0234.stg02


Comment: Reaction occurs in the glutaminase domain (CATH 3.40.50.880).



Mechanisms

Proton Transfer
Bimolecular Nucleophilic Addition

Mechanism Components

Bond Cleavage
Bond Formation
Bond Order Change
Enzyme-Substrate Bond Formation
Intermediate Formation
Overall Reactant Used

Amino acids involved in the reaction step.

Amino Acid Location of Function Activity Function
Gly59 Main Chain Amide spectator Electrostatic Stabiliser
Hydrogen Bond Donor
Cys86 Side Chain reactant Nucleophile
Hydrogen Bond Donor
Proton Donor
His181 Side Chain reactant Hydrogen Bond Acceptor
Hydrogen Bond Donor
Proton Acceptor
Glu183 Side Chain spectator Increase Basicity
Hydrogen Bond Acceptor
Tyr87 Main Chain Amide spectator Electrostatic Stabiliser
Hydrogen Bond Donor

Metal Cofactors involved in Step 02

Metal Type Metal Identity Chain Activity Function
magnesium MG 530 B spectator Not Present

Reactive Centre

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

View similar reactions in MACiE.


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