title: Isolation and characterization of thermostable chitinases from Bacillus licheniformis X-7u.
abstract: Four kinds of thermostable chitinase were isolated from the cell-free culture broth of Bacillus licheniformis X-7u by successive column chromatographies on Butyl-Toyopearl, Q-Sepharose, and Sephacryl S-200. We named the enzymes chitinases I(89 kDa), II(76 kDa), III(66 kDa) and IV(59 kDa). Chitinases II, III and IV possessed extremely high optimum temperatures (70-80 degrees C), showing remarkable heat stability. Chitinases II, III and IV produced (GlcNAc)2 and GlcNAc from colloidal chitin and chitinase I predominantly produced (GlcNAc)2. The action pattern of chitinase I on PN-(GlcNAc)4 also showed a stronger propensity to cleave off the (GlcNAc)2 unit from the non-reducing end than the other three chitinases. Chitinases II, III and IV catalyzed a transglycosylation reaction that converted (GlcNAc)4 into (GlcNAc)6.
authors.affiliation: Bioorganic Chemistry Division, Meiji Milk Products Co., Ltd., Odawara, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Takayanagi
authors.forename: K
authors.initials: K
authors.lastname: Ajisaka
authors.forename: Y
authors.initials: Y
authors.lastname: Takiguchi
authors.forename: K
authors.initials: K
authors.lastname: Shimahara
mesh_terms: D000596:Amino Acids / Q000302:isolation & purification; D001407:Bacillus / Q000201:enzymology*; D002384:Catalysis; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002688:Chitinases / Q000737:chemistry / Q000302:isolation & purification*; D006358:Hot Temperature; D008970:Molecular Weight
chemical_list: D000596:Amino Acids; D002688:Chitinases