title: Distinct roles of carbohydrate esterase family CE16 acetyl esterases and polymer-acting acetyl xylan esterases in xylan deacetylation.
abstract: Mass spectrometric analysis was used to compare the roles of two acetyl esterases (AE, carbohydrate esterase family CE16) and three acetyl xylan esterases (AXE, families CE1 and CE5) in deacetylation of natural substrates, neutral (linear) and 4-O-methyl glucuronic acid (MeGlcA) substituted xylooligosaccharides (XOS). AEs were similarly restricted in their action and apparently removed in most cases only one acetyl group from the non-reducing end of XOS, acting as exo-deacetylases. In contrast, AXEs completely deacetylated longer neutral XOS but had difficulties with the shorter ones. Complete deacetylation of neutral XOS was obtained after the combined action of AEs and AXEs. MeGlcA substituents partially restricted the action of both types of esterases and the remaining acidic XOS were mainly substituted with one MeGlcA and one acetyl group, supposedly on the same xylopyranosyl residue. These resisting structures were degraded to great extent only after inclusion of α-glucuronidase, which acted with the esterases in a synergistic manner. When used together with xylan backbone degrading endoxylanase and β-xylosidase, both AE and AXE enhanced the hydrolysis of complex XOS equally.
authors.affiliation: Department of Food and Environmental Chemistry, University of Helsinki, P.O. Box 27, 00014 Helsinki, Finland. Electronic address: sanna.koutaniemi@helsinki.fi.
authors.forename: S
authors.initials: S
authors.lastname: Koutaniemi
authors.forename: M P
authors.initials: MP
authors.lastname: van Gool
authors.forename: M
authors.initials: M
authors.lastname: Juvonen
authors.forename: J
authors.initials: J
authors.lastname: Jokela
authors.forename: S W
authors.initials: SW
authors.lastname: Hinz
authors.forename: H A
authors.initials: HA
authors.lastname: Schols
authors.forename: M
authors.initials: M
authors.lastname: Tenkanen
mesh_terms: D000107:Acetylation; D000115:Acetylesterase / Q000737:chemistry* / Q000378:metabolism; D001234:Aspergillus niger / Q000201:enzymology; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry / Q000378:metabolism; D005965:Glucuronates / Q000737:chemistry*; D006026:Glycoside Hydrolases / Q000737:chemistry; D006868:Hydrolysis; D009844:Oligosaccharides / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013379:Substrate Specificity; D014990:Xylans / Q000737:chemistry* / Q000378:metabolism
chemical_list: D005965:Glucuronates; D009844:Oligosaccharides; D014990:Xylans; C570991:xylooligosaccharide; C044967:4-O-methyl glucuronoxylan; D000115:Acetylesterase; C081851:acetylxylan esterase; D006026:Glycoside Hydrolases; C096734:alpha-glucuronidase; D043364:Endo-1,4-beta Xylanases
keywords: 4-O-methyl glucuronic acid; AE; AXE; Ac; AcUXOS; AcXOS; Acetyl xylan esterase; CE; CE16 acetyl esterase; GH; HPAEC-PAD; Mass spectrometry; O-acetyl; O-acetylated acidic MeGlcA-substituted xylooligosaccharides; O-acetylated neutral xylooligosaccharides; Xylan acetylation; acetyl esterase; acetyl xylan esterase; carbohydrate esterase; glycoside hydrolase; high performance anion exchange chromatography with pulsed amperometric detection