Department of Biotechnology, Human Nutrition and Food Commodities, University of Life Sciences in Lublin, Skromna 8, 20-704 Lublin, Poland.
J Microbiol Biotechnol. 2011 Aug;21(8):838-45. doi: 10.4014/jmb.1103.03028.
The present work describes the identification, purification, and characterization of bile salt hydrolase (BSH) from Bifidobacterium animalis subsp. lactis. The enzyme was purified to electrophoretic homogeneity by hydrophobic chromatography, ion-exchange chromatography and ultrafiltration. SDS-PAGE analysis of putative BSH and gel filtration revealed that the analyzed protein is presumably a tetramer composed of four monomers each of about 35 kDa. The purified enzyme was analyzed by liquid chromatography coupled to LTQ FT ICR mass spectrometry and unambiguously identified as a bile salt hydrolase from B. animalis. The isoelectric point of the studied protein was estimated to be around pH 4.9. The pH optimum of the purified BSH is between 4.7 to 6.5, and the temperature optimum is around 50 degrees C. The BSH of B. animalis could deconjugate all tested bile salts, with clear preference for glycine-conjugated bile salts over taurine-conjugated forms. Genetic analysis of the bsh showed high similarity to the previously sequenced bsh gene from B. animalis and confirmed the usefulness of bile salt hydrolase as a genetic marker for B. animalis identification.
本工作描述了从乳双歧杆菌亚种。动物分离、纯化和鉴定胆盐水解酶 (BSH)。该酶通过疏水层析、离子交换层析和超滤法电泳纯。推测 BSH 的 SDS-PAGE 分析和凝胶过滤表明，分析的蛋白质可能是由四个单体组成的四聚体，每个单体约 35 kDa。用液相色谱- LTQ FT ICR 质谱法分析纯化的酶，明确鉴定为乳双歧杆菌的胆盐水解酶。研究蛋白质的等电点估计在 pH 4.9 左右。纯化的 BSH 的 pH 最适范围在 4.7 到 6.5 之间，最适温度约为 50 摄氏度。乳双歧杆菌的 BSH 可以使所有测试的胆盐去结合，甘氨酰结合的胆盐明显优先于牛磺酰结合的形式。bsh 的遗传分析与先前从乳双歧杆菌分离的 bsh 基因具有高度相似性，证实了胆盐水解酶作为乳双歧杆菌鉴定的遗传标记的有用性。
