title: Purification and characterization of an esterase involved in cellulose acetate degradation by Neisseria sicca SB.
abstract: An esterase catalyzing the hydrolysis of acetyl ester moieties in cellulose acetate was purified 1,110-fold to electrophoretic homogeneity from the culture supernatant of Neisseria sicca SB, which can assimilate cellulose acetate as the sole carbon and energy source. The purified enzyme was a monomeric protein with a molecular mass of 40 kDa and the isoelectric point was 5.3. The pH and temperature optima of the enzyme were 8.0-8.5 and 45 degrees C. The enzyme catalyzed the hydrolysis of acetyl saccharides, p-nitrophenyl esters of short-chain fatty acids, and was slightly active toward aliphatic and aromatic esters. The K(m) and Vmax for cellulose acetate (degree of substitution, 0.88) and p-nitrophenyl acetate were 0.0162% (716 microM as acetyl content in the polymer) and 36.0 microM, and 66.8 and 39.1 mumol/min/mg, respectively. The enzyme was strongly inhibited by phenylmethylsulfonyl fluoride and diisopropyl fluorophosphate, which indicated that the enzyme was a serine esterase.
authors.affiliation: Department of Biochemistry, Osaka Municipal Technical Research Institute, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Moriyoshi
authors.forename: T
authors.initials: T
authors.lastname: Ohmoto
authors.forename: T
authors.initials: T
authors.lastname: Ohe
authors.forename: K
authors.initials: K
authors.lastname: Sakai
mesh_terms: D000595:Amino Acid Sequence; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D002482:Cellulose / Q000031:analogs & derivatives* / Q000378:metabolism; D002845:Chromatography; D004591:Electrophoresis, Polyacrylamide Gel; D004950:Esterases / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007700:Kinetics; D008969:Molecular Sequence Data; D009343:Neisseria / Q000201:enzymology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature
chemical_list: C005062:acetylcellulose; D002482:Cellulose; D004950:Esterases; D002265:Carboxylic Ester Hydrolases; C403303:cellulose acetate esterase