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Entry M0053    2.3.3.9    malate synthase

Next Step

Step 01

Asp631 deprotonates the methyl group of acetyl-CoA, which causes a rearrangement of the double bonds and the formation of an oxyanion.

GIF of Reaction Step M0053.stg01


Comment: Enzyme shows little discrimination with regard to the pro-R versus the pro-S hydrogens in fluoroacetyl-CoA, resulting in either a Z- or E-enolate intermediate. The developing negative charge is therefore stabilised by the adjacent positive charge (which is stabilised itself by the surrounding negatively charged groups in the active site) of the Arg338 [1].



Mechanisms

Proton Transfer
Assisted Keto-Enol Tautomerisation

Mechanism Components

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

Amino acids involved in the reaction step.

Amino Acid Location of Function Activity Function
Arg338 Side Chain spectator Hydrogen Bond Donor
Electrostatic Stabiliser
Asp270 Side Chain spectator Electrostatic Stabiliser
Hydrogen Bond Acceptor
Asp631 Side Chain reactant Hydrogen Bond Acceptor
Proton Acceptor
Glu272 Side Chain spectator Electrostatic Stabiliser
Hydrogen Bond Acceptor

Metal Cofactors involved in Step 01

Metal Type Metal Identity Chain Activity Function
magnesium MG 3001 A spectator Substrate Binding

Reactive Centre

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

View similar reactions in MACiE.


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