Dioxygenase regioselectants

Lipoxygenase (LOX) is a non-haem, iron-containing dioxygenase that catalyses the regioselective and enantioselective dioxygenation of unsaturated fatty acids containing at least one (Z,Z)-l,4-pentadienoic system. For instance, LOX from soy converts linoleic acid to the (S)-13-hydroperoxide [1]. 

Advantageous use of homochiral cyclohexadiene-cis-l,2-diol, available by means of biocatalytic oxidation of chlorobenzene with toluene dioxygenase, has enabled the synthesis of all four enantiomerically pure C18-sphingosines (Nugent, 1998), which are known inhibitors of protein kinase C and important in cellular response mediation for tumor promoters and growth factors. The four requisite diastere-omers of azido alcohol precursors were accessed by regioselective opening of epoxides with either azide or halide ions. 

Finn, K.J., Pavlyuk, O. and Hudlicky, T. (2005) Toluene dioxygenase-mediated oxidation of bromo(methylsulfanyl) benzenes. Absolute configuration of metabolites and evaluation of chemo-and regioselectivity trends. Collection of Czechoslovak Chemical Communications, 70,1709 1726. 

Yildirim, S., Franco, T., Wohlgemuth, R., Kohler, H.P., Witholt, B. and Schmid, A. (2005) Recombinant chlorobenzene dioxygenase from Pseudomonas sp. P51 a biocatalyst for regioselective oxidation of aromatic nitriles. Advanced Synthesis Catalysis, 347,1060 1073. 

Fig. 1 Major fragment classes of carotenoid biodegradation assumed to be formed by regioselective attack of dioxygenases.

Seo J, Kang S-I, Ryu J-Y, Lee Y-J, Park KD, Kim M, Won D, Park H-Y, Ahn J-H, Chong Y, Kanaly RA, Han J, Hur H-G (2010) Location of flavone B-ring controls regioselectivity and stereoselectivity of naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4. Appl Microbiol Biotechnol 86 1451-1462... 

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