Purification and Characterization of an Esterase Involved in Cellulose Acetate Degradation by Neisseria sicca SB

概要

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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℃. The enzyme catalyzed the hydrolysis of acetyl saccharides, p-nitro-phenyl esters of short-chain fatty acids, and was slightly active toward aliphatic and aromatic esters. The K_m and V_<max> for cellulose acetate (degree of substitution, 0.88) and p-nitrophenyl acetate were 0.0162% (716μM as acetyl content in the polymer) and 36.0μM, and 66.8 and 39.1 μmol/min/mg, respectively. The enzyme was strongly inhibited by phenylmethylsulfonyl fluoride and diisopropyl fluorophosphate, which indicated that the enzyme was a serine esterase.
社団法人日本農芸化学会の論文
1999-10-23