Hydrolases;
Acting on ester bonds;
Phosphoric-monoester hydrolases
BRITE hierarchy

5-(methylsulfanyl)-2,3-dioxopentyl-phosphate phosphohydrolase (isomerizing)

5-(methylsulfanyl)-2,3-dioxopentyl phosphate + H2O = 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one + phosphate (overall reaction) [RN:R07395];
(1a) 5-(methylsulfanyl)-2,3-dioxopentyl phosphate = 2-hydroxy-5-(methylsulfanyl)-3-oxopent-1-enyl phosphate (probably spontaneous) [RN:R07393];
(1b) 2-hydroxy-5-(methylsulfanyl)-3-oxopent-1-enyl phosphate + H2O = 1,2-dihydroxy-5-(methylsulfanyl)pent-1-en-3-one + phosphate [RN:R07394]

R07393 R07394 R07395
Reaction

5-(methylsulfanyl)-2,3-dioxopentyl phosphate [CPD:C15650];
H2O [CPD:C00001];
2-hydroxy-5-(methylsulfanyl)-3-oxopent-1-enyl phosphate [CPD:C15651]

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

EC 3.1.3.77 created 2006