:Futalosine hydrolase

{{Infobox enzyme

| Name = Futalosine hydrolase

| EC_number = 3.2.2.26

| CAS_number =

| GO_code =

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Futalosine hydrolase ({{EC number|3.2.2.26}}, futalosine nucleosidase, MqnB) is an enzyme with systematic name futalosine ribohydrolase.{{cite journal | vauthors = Hiratsuka T, Furihata K, Ishikawa J, Yamashita H, Itoh N, Seto H, Dairi T | title = An alternative menaquinone biosynthetic pathway operating in microorganisms | journal = Science | volume = 321 | issue = 5896 | pages = 1670–3 | date = September 2008 | pmid = 18801996 | doi = 10.1126/science.1160446 }} This enzyme catalyses the following chemical reaction

: futalosine + H₂O $\backslash rightleftharpoons$ dehypoxanthine futalosine + hypoxanthine

This enzyme catalyses the second step of menaquinone biosynthesis.