Description
This bifunctional enzyme first enolizes the substrate to form the intermediate 2-hydroxy-5-(methylthio)-3-oxopent-1-enyl phosphate, which is then dephosphorylated to form the acireductone 1,2-dihydroxy-5-(methylthio)pent-1-en-3-one. The acireductone represents a branch point in the methione-salvage pathway as it is used in the formation of formate, CO and 3-(methylthio)propanoate by EC 1.13.11.53 [acireductone dioxygenase (Ni2+-requiring)] and of formate and 4-methylthio-2-oxobutanoate either by a spontaneous reaction under aerobic conditions or by EC 1.13.11.54 {acireductone dioxygenase [iron(II)-requiring]}