title: [Extracellular ribonuclease from Bacillus thuringiensis].
abstract: The ability of the strain Bacillus thuringiensis var. subtoxicus to produce extracellular ribonuclease (ribonuclease Bt) was studied. It was found that the culture medium possesses a RNA-depolymerizing activity whose maximum is observed 4-5 hours after the beginning of the linear growth phase. A three-step chromatography of the culture extract on phosphocellulose resulted in a homogeneous enzyme with a molecular mass of 12000 Da. The enzyme showed the maximum activity towards RNA at pH 8.5, catalyzed the hydrolysis of polyribonucleotides and guanosine-2',3'-cyclophosphate. Hence, the enzyme can be related to base-nonspecific cyclizing ribonucleases showing the guanylic specificity towards nucleoside-2',3'-cyclophosphates.
authors.forename: N K
authors.initials: NK
authors.lastname: Chepurnova
authors.forename: D L
authors.initials: DL
authors.lastname: Liakhov
authors.forename: V O
authors.initials: VO
authors.lastname: Rechinskiĭ
authors.forename: M Ia
authors.initials: MIa
authors.lastname: Karpeĭskiĭ
mesh_terms: D001413:Bacillus thuringiensis / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D012260:Ribonucleases / Q000302:isolation & purification*; D013379:Substrate Specificity
chemical_list: D012260:Ribonucleases
vernacular_title: Vnekletochnaia ribonukleaza iz Bacillus thuringiensis.