title: Mode of action on deacetylation of acetylated methyl glycoside by cellulose acetate esterase from Neisseria sicca SB.
abstract: The regioselective deacetylation of purified cellulose acetate esterase from Neisseria sicca SB was investigated on methyl 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside and 2,3,4,6-tetra-O-acetyl-beta-D-galactopyranoside. The substrates were used as model compounds of cellulose acetate in order to estimate the mechanism for deacetylation of cellulose acetate by the enzyme. The enzyme rapidly deacetylated at position C-3 of methyl 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside to accumulate 2,4,6-triacetate as the main initial reaction product in about 70% yield. Deacetylation was followed at position C-2, and generated 4,6-diacetate in 50% yield. The enzyme deacetylated the product at positions C-4 and C-6 at slower rates, and generated 4- and 6-monoacetates at a later reaction stage. Finally, it gave a completely deacetylated product. For 2,3,4,6-tetra-O-acetyl-beta-D-galactopyranoside, CA esterase deacetylated at positions C-3 and C-6 to give 2,4,6- and 2,3,4-triacetate. Deacetylation proceeded sequentially at positions C-3 and C-6 to accumulate 2,4-diacetate in 55% yield. The enzyme exhibited regioselectivity for the deacetylation of the acetylglycoside.
authors.affiliation: Department of Environmental Technology, Osaka Municipal Technical Research Institute. moriyosi@omtri.city.osaka.jp
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Moriyoshi
authors.forename: Hayato
authors.initials: H
authors.lastname: Yamanaka
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohmoto
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Ohe
authors.forename: Kiyofumi
authors.initials: K
authors.lastname: Sakai
mesh_terms: D000107:Acetylation; D002265:Carboxylic Ester Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D002855:Chromatography, Thin Layer; D004187:Disaccharides; D005690:Galactose / Q000737:chemistry / Q000378:metabolism; D005965:Glucuronates; D006027:Glycosides / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008757:Methylglucosides / Q000737:chemistry / Q000378:metabolism; D042808:Neisseria sicca / Q000201:enzymology*; D013379:Substrate Specificity; D013997:Time Factors
chemical_list: D004187:Disaccharides; D005965:Glucuronates; D006027:Glycosides; D008757:Methylglucosides; C027020:methylglucoside; C059554:O-(glucuronic acid 2-sulfate)-(1--4)-O-(2,5)-anhydromannitol 6-sulfate; D002265:Carboxylic Ester Hydrolases; C403303:cellulose acetate esterase; D005690:Galactose