A series of experiments have been proposed to elucidate the mechanisms of two enzymes, dopamine Beta-monooxygenase and peptidylglycine alpha-hydroxylating monooxygenase. These enzymes play an important role in the synthesis and regulation of hormones. Many aspects in the mechanisms of these enzymes are still unresolved. We propose to trap and characterize several of the intermediates generated by the enzymes throughout the catalytic cycle, using Co(ll) complexes. These complexes will also allow us to probe the redox properties of the copper cofactors involved in these processes. Studies will be carried out on both enzymes in order to draw comparisons between the two systems.