کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9616803 | 48895 | 2005 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Comparison and functional characterisation of three homologous intracellular carboxylesterases of Bacillus subtilis
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
کاتالیزور
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Comparison and functional characterisation of three homologous intracellular carboxylesterases of Bacillus subtilis Comparison and functional characterisation of three homologous intracellular carboxylesterases of Bacillus subtilis](/preview/png/9616803.png)
چکیده انگلیسی
Enzymatic hydrolysis of racemic mixtures may provide an attractive method for the enantiopure production of chiral pharmaceuticals. For example, the carboxylesterase NP of Bacillus subtilis Thai I-8 is an excellent biocatalyst in the kinetic resolution of NSAID esters, such as naproxen and ibuprofen methyl esters. Two homologues of this enzyme were identified when the genome sequence of B. subtilis 168 was revealed in 1997. We characterised one of the homologous, YbfK, as a very enantioselective 1,2-O-isopropylidene-sn-glycerol caprylate esterase, while only modest enantioselectivity towards the naproxen ester was observed. The other homologue, the carboxylesterase NA has not been characterised yet. The purpose of the present study was to fully characterise these three highly homologous esterases with respect to their applicability towards the enantiospecific hydrolysis of a wide range of compounds. The esterase genes were cloned and expressed in B. subtilis using a combination of two strong promotors in a multi-copy vector. After purification of the enzymes from the cytoplasm of B. subtilis, the biochemical and enantioselective properties of the enzymes were determined. Although all carboxylesterases have similar physico-chemical properties, comparison of their specific activities and enantioselectivities towards several compounds revealed rather different substrate specificities. We conclude that carboxylesterase NP and carboxylesterase NA are particularly suited for the enzymatic conversion of naproxen esters, while YbfK offers enantiopure (+)-IPG from its caprylate ester. Given the carboxylesterase activities of the esterases it has been proposed to rename the nap gene of B. subtilis 168 into cesA and the ybfK gene into cesB.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Catalysis B: Enzymatic - Volume 32, Issues 5â6, 1 March 2005, Pages 261-270
Journal: Journal of Molecular Catalysis B: Enzymatic - Volume 32, Issues 5â6, 1 March 2005, Pages 261-270
نویسندگان
Melloney J. Dröge, Rein Bos, Ykelien L. Boersma, Wim J. Quax,