Styrene monooxygenase

• UniProt: Q55080

Styrene monooxygenase is an enzyme in bacteria.

Catalyzing the chemical reaction

As the first step of aerobic styrene degradation pathway of bacteria. The product 2- phenyloxirane ( styrene oxide ) can be implemented by a styrene oxide isomerase ( SOI) to phenylacetaldehyde. The latter is further oxidized by a phenylacetaldehyde dehydrogenase (EC 1.2.1.39 ) to phenylacetic acid, a key intermediate.

According to the EC number, the enzyme ( SMO) belongs to the group of oxidoreductases and is dependent on the cofactor FAD, so it was classified as external flavoprotein monooxygenase ( Subgroup: Type E). It forms a two-component system comprising a reductase ( StyB, StyA2B ). Reductase only uses NADH to reduce FAD which is then transferred to the oxygenase ( StyA, StyA1 ). Two types of enzyme have been documented: StyA / StyB (referred to as E1), first described in Pseudomonas species, and StyA1/StyA2B ( called E2), first described in Actinobacteria. The E1 - type seems to be more common in nature and consists of a single monooxygenase ( StyA ), which is supported by a single reductase ( StyB ). However, the E2 - type is composed differently. It consists of a major monooxygenase ( StyA1 ) and a fusion protein of monooxygenase and reductase ( StyA2B ). The latter is the source of reduced FAD ( reductase) and also has some side oxygenase activity. So far, all lead styrene monooxygenases from an enantioselective epoxidation of styrene and chemically analogous compounds, which makes them interesting for biotechnological applications.