Catalyzes the deamination of aminodeoxyfutalosine (AFL) into futalosine (FL), a step in the biosynthesis of menaquinone (MK, vitamin K2). 6-amino-6-deoxyfutalosine + H(+) + H2O = futalosine + NH4(+) Binds 1 zinc ion per subunit. Quinol/quinone metabolism; menaquinone biosynthesis. Belongs to the metallo-dependent hydrolases superfamily. Adenosine and AMP deaminases family.