Styrene oxide isomerase (SOI) [EC 5.3.99.7], most probably located in the cell wall, was partially purified from Coiynebacterium sp. AC-5 cells grown in a styrene gas atmospheres. The enzyme catalyzed the isomerization reaction to give phenylacetaldehyde, but did not catalyze its reverse reaction. The optimum pH of the reaction was around 7.0, and the enzyme was unstable below pH 6.0. The Km toward styrene oxide was very low (7.7 × 10(-5) m), indicating its high affinity for styrene oxide. The enzyme showed strict substrate specificity, and epoxide compounds other than styrene oxide did not serve as substrates. (S)-Styrene oxide was preferentially converted by the enzyme, compared with the (R)-isomer. The possible application of SOI as a biocatalyst is also discussed.
A novel phenylacetaldehyde reductase was purified about 50-fold to homogeneity from Corynebacterium sp. strain ST-10, which can assimilate gaseous styrene as the sole carbon and energy source. The enzyme was inductively synthesized when grown on gaseous styrene and had an important role in styrene metabolism in vivo. The enzyme had a molecular weight of 155,000 and was composed of four identical subunits (molecular weight, 42,000). The enzyme catalyzed the reduction of not only phenylacetaldehyde but also various aldehydes and ketones; however, it did not catalyze the reverse reaction, the dehydrogenation of 2-phenylethanol. The enzyme required NADH as a cofactor and showed no activity with NADPH; therefore, it was defined as an NADH-dependent phenylacetaldehyde reductase. The enzyme stereospecifically produced (S)-(؊)-1-phenylethanol from acetophenone; therefore, it would be useful as a biocatalyst.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.