Other minor phase I reactions included isopropyl hydroxylation (F3, F5), A-depentylation (F4), oxidative deamination of the carboxamide group (F10-F12), and isopropyl dehydrogenation (F11, F12).
F10, F11, and F12 were minor third and fourth generation metabolites combining oxidative defluorination and subsequent carboxylation and oxidative deamination (F10), oxidative defluorination, oxidative deamination, and isopropyl dehydrogenation (F11) and oxidative defluorination and subsequent carboxylation, oxidative deamination, and isopropyl dehydrogenation (F12).
Monoamine oxidases (MAOs) are flavoproteins which catalyze the
oxidative deamination of a variety of neurotransmitters, such as noradrenaline, dopamine, and serotonin, as well as different exogenous and endogenous amines (i.e., tyramine, benzylamine, etc.) to their corresponding aldehydes.
3,4-Dihydroxyphenylacetaldehyde (DOPAL) is an endogenous catecholaldehyde produced by
oxidative deamination of dopamine.
VMA may also be produced by the
oxidative deamination of normetanephrine and metanephrine or by O-methylation of dihydroxymandelic acid, a minor metabolite of norepinephrine (2,3).