Catalyzes the deamination of aminodeoxyfutalosine (AFL) into futalosine (FL), a step in the biosynthesis of menaquinone (MK, vitamin K2). Is very poorly efficient on 1-(6-amino-9H-purin-9-yl)-1-deoxy-N-ethyl-beta-D-ribofuranuronamide (NECA), adenosine, 5'-methylthioadenosine, 5'-deoxyadenosine, 2'-deoxyadenosine, and AMP as substrate. 6-amino-6-deoxyfutalosine + H(+) + H2O = futalosine + NH4(+) Binds 1 zinc ion per subunit. kcat is 6.8 sec(-1) with aminodeoxyfutalosine as substrate. kcat is 0.007 sec(-1) with 1-(6-amino-9H-purin-9-yl)-1-deoxy-N-ethyl-beta-D-ribofuranuronamide as substrate. Quinol/quinone metabolism; menaquinone biosynthesis. Belongs to the metallo-dependent hydrolases superfamily. Adenosine and AMP deaminases family.