Catalyzes the deamination of aminodeoxyfutalosine (AFL) into futalosine (FL), a step in the biosynthesis of menaquinone (MK, vitamin K2). To a lesser extent, can also deaminate adenosine, 5'-methylthioadenosine, 5'-deoxyadenosine, and 2'-deoxyadenosine. 6-amino-6-deoxyfutalosine + H(+) + H2O = futalosine + NH4(+) Binds 1 zinc ion per subunit. kcat is 3.8 sec(-1) with aminodeoxyfutalosine as substrate. kcat is 0.40 sec(-1) with 5'-methylthioadenosine as substrate. Quinol/quinone metabolism; menaquinone biosynthesis. Belongs to the metallo-dependent hydrolases superfamily. Adenosine and AMP deaminases family.