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    Durch Überexpression in der Hefe Pichia pastoris zu erhöhter Enantioselektivität : ein neues Kapitel in der Anwendung von Schweineleberesterase
    (2001) Musidlowska, Anna; Lange, Stefan; Bornscheuer, Uwe Theo
    Lipases and Esterases can be used as efficient biocatalysts for the preparation of a wide variety of optically pure compounds. Whereas a range of lipases - especially of microbial origin - are commercially available, only a few esterases can be obtained for the kinetic resolution of racemates or desymmetrization. In the majority of publications, pig liver esterase (PLE) is used, which is isolated from pig liver by extraction. Although it could be demonstrated, that this preparation can convert a broad range of compounds at partially very high stereoselectivity, its application is encountered with a number of disadvantages.
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    Cloning, expression and characterisation of CYP102A2, a self-sufficient P450 monooxygenase from Bacillus subtilis
    (2004) Budde, Michael; Maurer, Steffen Christian; Schmid, Rolf D.; Urlacher, Vlada B.
    The gene encoding CYP102A2, a novel P450 monooxygenase from Bacillus subtilis, was cloned and expressed in Escherichia coli. The recombinant enzyme formed was purified by immobilised metal chelat affinity chromatography (IMAC) and characterised. CYP102A2 is a 119 kDa self-sufficient monooxygenase, consisting of an FMN/FAD–containing reductase domain and a heme domain. The deduced amino acid sequence of CYP102A2 exhibits a high level of identity with the amino acid sequences of CYP102A1 from Bacillus megaterium (59%) and CYP102A3 from Bacillus subtilis (60%). In reduced, CO-bound form, the enzyme shows a typical Soret band at 450 nm. It catalyses the oxidation of even- and odd-chain saturated and unsaturated fatty acids. In all reactions investigated, the products were the respective ù-3, ù-2 and ù-1 hydroxylated fatty acids. Activity was highest towards oleic and linoleic acid (KM=17.4 ± 1.4 ìM, kcat= 2244 ± 72 min-1), linoleic acid (KM=12.25 ± 1.8 ìM, kcat= 1950 ± 84 min-1). Comparison of CYP102A2 homology model to CYP102A1 crystal structure revealed significant differences in the substrate access channels, which might explain the differences in catalytic properties of these two enzymes.