Catalyzes the hydrolysis of futalosine (FL) to dehypoxanthine futalosine (DHFL) and hypoxanthine, a step in the biosynthesis of menaquinone (MK, vitamin K2). Does not accept aminodeoxyfutalosine (AFL) as a substrate. futalosine + H2O = dehypoxanthine futalosine + hypoxanthine Quinol/quinone metabolism; menaquinone biosynthesis. Mutants require menaquinone for their growth. Belongs to the PNP/UDP phosphorylase family. Futalosine hydrolase subfamily. Truncated N-terminus. Truncated N-terminus.