(1) fructose-1,6P2 - AMP - FBP*:Mg_super_2+_endsuper_ - TIGAR* -> fructose-6P (2) FBP*+Mg_super_2+_endsuper_ -> FBP*:Mg_super_2+_endsuper_
stoechiometry tetramer of FBP, FBP1 known to bind 3 Mg_super_2+_endsuper_ per subunit