Flavoenzymes: diverse catalysts with recurrent features

Many biochemical processes exploit the extraordinary versatility of flavoen zymes and their flavin cofactors, Flavoproteins are now known to have a var iety of folding topologies but a careful examination of their structures su ggests that there are recurrent features in their catalytic apparatus. The flavoenzymes that catalyse dehydrogenation reactions share a few invariant features in the hydrogen-bond interactions between their protein and flavin constituents. Similarly, the positioning of the reactive part of the subst rate with respect to the cofactor is generally conserved. Modulation of sub strate and cofactor reactivity and exact positioning of the substrate are k ey elements in the mode of action of these enzymes.