title: Molecular characterization of bile salt hydrolase from Bifidobacterium animalis subsp. lactis Bi30.
abstract: 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.
authors.affiliation: Department of Biotechnology, Human Nutrition and Food Commodities, University of Life Sciences in Lublin, Skromna 8, 20-704 Lublin, Poland. piotr.jarocki@wp.pl
authors.forename: Piotr
authors.initials: P
authors.lastname: Jarocki
mesh_terms: D000581:Amidohydrolases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001644:Bifidobacterium / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D055503:Protein Multimerization
chemical_list: D001426:Bacterial Proteins; D000581:Amidohydrolases; C023154:choloylglycine hydrolase