Characterization of the smallest dimeric bile salt hydrolase from a thermophile Brevibacillus sp. |
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Authors: | N Sridevi Sameer Srivastava Bashir Mohammad Khan Asmita Ashutosh Prabhune |
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Institution: | (1) Biochemical Sciences Division, National Chemical Laboratory, Pune, 411008, India;(2) Plant Tissue Culture Division, National Chemical Laboratory, Pune, India |
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Abstract: | A thermophilic microorganism producing bile salt hydrolase was isolated from hot water springs, Pali, Maharashtra, India.
This microorganism was identified as Brevibacillus sp. by 16S rDNA sequencing. Bile salt hydrolase (BSH) was purified to homogeneity from this thermophilic source using Q-sepharose
chromatography and its enzymatic properties were characterized. The subunit molecular mass of the purified enzyme was estimated
to be 28 kDa by SDS-PAGE and, 28.2 kDa by MALDI-TOF analysis. The native molecular mass was estimated to be 56 kDa by gel
filtration chromatography, indicating the protein to be a homodimer. The pH and temperature optimum for the enzyme catalysis
were 9.0 and 60°C, respectively. Even though BSH from Brevibacillus sp. hydrolyzed all of the six major human bile salts, the enzyme preferred glycine conjugated substrates with apparent K
M and k
cat values of 3.08 μM and 6.32 × 102 s−1, respectively, for glycodeoxycholic acid. The NH2-terminal sequence of the purified enzyme was determined and it did not show any homology with other bacterial bile salt hydrolases.
To our knowledge, this is the first report describing the purification of BSH to homogeneity from a thermophilic source.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. |
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Keywords: | Purification Bile salt hydrolase Brevibacillus sp Dimeric intracellular enzyme Thermophile |
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