Heme monoxygenases

Sligar SG, Luthra A, Denisov 1, Davydov R, Hoffman B, Mak P, Kincaid J (2010) Oxygen intermediates in heme monoxygenases. Pacifichem 2010, international chemical congress of pacific basin societies, Honolulu, HI, United States, 15-20 Dec 2010 BIOL-102... 

Tyrosine hydroxylase (TH) is an enzyme that catalyzes the hydroxylation of tyrosine to 3,4-dihydroxypheny-lalanine in the brain and adrenal glands. TH is the rate-limiting enzyme in the biosynthesis of dopamine. This non-heme iron-dependent monoxygenase requires the presence of the cofactor tetrahydrobiopterin to maintain the metal in its ferrous state. 

Figure 2.6 Schematic representation of the heme group orientation and different substrate accessibility in the heme active sites in monoxygenases and peroxidases.

The selective catalytic epoxidation of alkenes has become the most important reaction catalyzed by heme proteins in organic synthesis. As described above, the monoxygenase activity of a heme peroxidase is restricted to CPO due to the open substrate access of the ferryl subunit for this enzyme. HRP catalyzes epoxidations only after mutagenetic variations, as shown for the substrate trans-P-methylstyrene [234]. An exception of this rule is the regioselective epoxidation of (T.TJ-piperylpiperidide, which is successfully catalyzed by native HRP [265]. 

P450 Monoxygenase -Oxidase 0 Heme Oxygenase Peroxygenase Peroxidase/Catalase -... 

Monoxygenase heme or non-heme models for the hydroxylation of RH to ROH. The catalyst... 

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