title: A sennoside-hydrolyzing beta-glucosidase from Bifidobacterium sp. strain SEN is inducible.
abstract: Bifidobacterium sp. strain SEN was isolated and characterized by hydrolytic conversion of sennosides to sennidins (Akao et al., Appl. Environ. Microbiol., 60, 1041 (1994)). The sennoside-hydrolyzing capacity of the strain SEN was disappeared following the addition of glucose to the media in spite of good bacterial growth and potent activity hydrolyzing p-nitrophenyl beta-D-glucopyranoside (pNPG). In a fructose-containing medium, no such suppressing effect was shown. Following a 10 h incubation in 50 mM potassium phosphate buffer (pH 7.4), the sennoside-hydrolyzing activity of the bacterium increased, dose-dependently, with the addition of sennoside B. Inhibition of the substrate-induced increase in sennoside-hydrolyzing activity was observed following the addition of some antibiotics (chloramphenicol, streptomycin, and rifampicin). In particular, chloramphenicol completely inhibited the increase of sennoside-hydrolyzing activity while 38% pNPG-hydrolyzing activity remained. It is suggested that the strain SEN produces two different beta-glucosidases of which the sennoside-hydrolyzing enzyme is inducible. In addition, the glucosides pNPG, esculin, salicin, or amygdalin stimulated the induction of the sennoside beta-glucosidase, but less markedly than sennoside. Sennidin A or sugars (glucose, fructose, cellobiose, or maltose) did not induce the enzyme.
authors: Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
authors: L
authors: L
authors: Yang
authors: T
authors: T
authors: Akao
authors: K
authors: K
authors: Kobashi
authors: M
authors: M
authors: Hattori
mesh_terms: D000880:Anthraquinones / Q000302:isolation & purification / Q000378:metabolism*; D001644:Bifidobacterium / Q000201:enzymology* / Q000235:genetics; D002701:Chloramphenicol / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D005243:Feces / Q000382:microbiology; D005947:Glucose / Q000494:pharmacology; D005960:Glucosides / Q000494:pharmacology; D006801:Humans; D009598:Nitrophenylgalactosides / Q000494:pharmacology; D012329:RNA, Bacterial / Q000096:biosynthesis; D012676:Senna Extract; D000081226:Sennosides; D013379:Substrate Specificity; D001617:beta-Glucosidase / Q000037:antagonists & inhibitors / Q000096:biosynthesis*
chemical_list: D000880:Anthraquinones; D005960:Glucosides; D012329:RNA, Bacterial; D000081226:Sennosides; D009598:Nitrophenylgalactosides; C059200:4-nitrophenylgalactoside; D002701:Chloramphenicol; D012676:Senna Extract; D001617:beta-Glucosidase; D005947:Glucose