4CFS:
reference: Origin of the proton-transfer step in the cofactor-free 1-H-3-hydroxy-4-oxoquinaldine 2,4- dioxygenase: Effect of the basicity of an active site His residue., Hernandez-Ortega A, Quesne MG, Bui S, Heuts DP, Steiner RA, Heyes DJ, de Visser SP, Scrutton NS, J Biol Chem. 2014 Jan 30. PMID: 24482238

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