Oxygenases: mechanisms and structural motifs for O-2 activation

Recent structural and mechanistic analysis of oxygenase enzymes together with the study of biomimetic model reactions have provided new insights into the catalytic mechanisms of oxygenase-catalysed reactions. High-valent iron-oxo intermediates have been implicated in heme- and pterin-dependent monooxygenases. Structural motifs have been identified for binding of non-heme iron(II) (His,His,Glu) and iron(III) (His(2)Tyr(2)) in non-heme-dependent dioxygenases, but additional factors influencing the choice of reaction pathway are emerging from model studies