Entry M0326 220.127.116.11 pyruvate kinase
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Thr237 and the Mn(II) cation increase the acidity of water through hydrogen bonding and charge stabilisation, respectively, generating a specific acid to act towards the enolate intermediate.
Comment: A solvent molecule at the active site stereospecifically protonates the enolate at the 2-si face of the double bond to form keto pyruvate. The Thr237 residue has been shown to influence the pKa of the specific acid, and is positioned within the active site to influence the stereo-selectivity of the protonation, although kinetic and pH studies have shown the proton to originate from a solvent molecule . The divalent cation is thought to enhance the acidity of the solvent molecule, rather than the monovalent cation .
Amino acids involved in the reaction step.
Metal Cofactors involved in Step 02
||Bonds Changed in Order
||Atom Types Involved
The C-C bond changes from a double to single bond
View similar reactions in MACiE.