Alkane monooxygenase

Figure 1. Classification of oxidoreductases with a focus on enzymes capable of sp3-carbon oxyfunctionalization. MMO, methane monooxygenase AMO, alkane monooxygenase XMO, xylene monooxygenase. The most prominent enzyme classes in respect of sp3-carbon oxyfunctionalization are shown in bold.

Figure 6. Hydroxylation of alkanes catalyzed by recombinant microbes harboring the alkane monooxygenase (AMO) of P. putida GPol (formerly known as P. oleovorans GPol). A fraction ofthe broad substrate spectrum of AMO is shown [102].

Figure 8. Hydroxylation of L-limoneneto (-)-perillyl alcohol by cytochrome P450. Growing cells of P. putida GPol2 (pG Ec47AB) (pCom8-PFRl 500) containing the P450 alkane monooxygenase of Mycobacterium sp. strain HXN-1500 are used as catalyst.

Austin, R.N., Chang, H.-K., Zylstra, G.J., and Groves, J.T. (2000) The non-heme diiron alkane monooxygenase of Pseudomonas oleovorans (AlkB) hydroxylates via a substrate radical intermediate, J. Am. Chem. Sac. 122, 11747-11748. 

A formal heterogeneous analog of alkane monooxygenases has been described by Lin and Sen [57f. The system involves a metal catalyst (palladium) and a co-reductant (carbon monoxide). Ethane is transformed into acetic acid at temperatures < 1(X) °C. The proposed mechanism for this reaction is shown in Scheme IX.6. 

Whyte LG, Schultz A, Van Beilen JB, Luz AP, Pellizari V, Labbe D, Greer CW (2002) Prevalence of alkane monooxygenase genes in Arctic and Antarctic hydrocarbon-contaminated and pristine soils. FEMS Microbiol Ecol 41 141-150... 

Buhler, Schmid, and coworkers [36] described the development of a recombinant whole-cell biocatalyst for the direct terminal alkylamino-functionalization of fatty acid methyl esters (e.g., dodecanoic acid methyl ester). The model substrate was dodecanoic acid methyl ester, which was oxidized by an alkane monooxygenase (AlkBGT) from Pseudomonas putida GPol to the corresponding... 

Scheme 3.15 Terminal amino functionalization of dodecanoic acid methyl ester with E. coli BL21 (DE3) (pBTlO, pTA) containing alkane monooxygenase AlkBGT and ca-transaminase CV2025.

Microorganisms that use gaseous olefins as a carbon source are widely exist in nature, and they typically produce nonheme iron-dependent alkene/alkane monooxygenases. Although in a lot of cases, the identification of the key enzyme hasn t been attempted many of those alkene-utilizing bacteria have been used in the asymmetric epoxidation of aliphatic alkenes with high stereoselectivities [26]. 

The alkane-utilizing bacteria P. oleovorans, which contains a three-component alkane monooxygenase, also accepts terminal olefins as substrates for asymmetric epoxidation [79]. For example, it can catalyze the asymmetric epoxidation of 1,7-octadiene to (R)-7,8-epoxyoctene and (R)-l,2,7,8-diepoxyoctane and also for the production of 1,2-epoxydecane and 1,2-epoxyoctane with moderate stereoselectivity (60-84%ee) [80,81]. 

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