Role of endo-1,4-beta-glucanases from neisseria sicca SB in synergistic degradation of cellulose acetate.
An enzyme hydrolyzing beta-1,4 bonds in cellulose acetate was purified 10.5-fold to electrophoretic homogeneity from a culture supernatant of Neisseria sicca SB, which assimilate cellulose acetate as the sole carbon and energy source. The enzyme was an endo-1,4-beta-glucanase, to judge from the substrate specificity and hydrolysis products of cellooligosaccharides, we named it endo-1,4-beta-glucanase I (EG I). Its molecular mass was 50 kDa, 9 kDa larger than EG II from this strain, and its isoelectric point was 5.0. Results of N-terminal and inner-peptide sequences of both enzymes, and a similarity search, suggested that EG I contained a carbohydrate-binding module at the N-terminus and that EG II lacked this module. The pH and temperature optima of EG I were 5.0-6.0 and 45 degrees C. It hydrolyzed water-soluble cellulose acetate (degree of substitution, 0.88) and carboxymethyl cellulose. The Km and Vmax for these compounds were 0.296% and 1.29 micromol min(-1) mg(-1), and 0.448% and 13.6 micromol min(-1) mg(-1), respectively. Both glucanases and cellulose acetate esterase from this strain degraded water-insoluble cellulose acetate synergistically.
Moriyoshi
Kunihiko
K
Department of Biochemistry, Osaka Municipal Technical Research Institute, 1-6-50 Morinomiya, Joto-ku, Osaka 536-8553, Japan.
Ohmoto
Takashi
T
Ohe
Tatsuhiko
T
Sakai
Kiyofumi
K
D000327:Adsorption; D000595:Amino Acid Sequence; D001673:Biodegradation, Environmental; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D002480:Cellulase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002482:Cellulose / Q000031:analogs & derivatives* / Q000378:metabolism*; D002848:Chromatography, DEAE-Cellulose; D004591:Electrophoresis, Polyacrylamide Gel; D005936:Glucans / Q000737:chemistry; D006868:Hydrolysis; D007700:Kinetics; D008969:Molecular Sequence Data; D009343:Neisseria / Q000201:enzymology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D005936:Glucans; C005062:acetylcellulose; D002482:Cellulose; D002265:Carboxylic Ester Hydrolases; C403303:cellulose acetate esterase; D002480:Cellulase