title: Enzymatic synthesis of beta-xylanase substrates: transglycosylation reactions of the beta-xylosidase from Aspergillus sp.
abstract: A beta-D-xylosidase with molecular mass of 250+/-5 kDa consisting of two identical subunits was purified to homogeneity from a cultural filtrate of Aspergillus sp. The enzyme manifested high transglycosylation activity in transxylosylation with p-nitrophenyl beta-D-xylopyranoside (PNP-X) as substrate, resulting in regio- and stereoselective synthesis of p-nitrophenyl (PNP) beta-(1-->4)-D-xylooligosaccharides with dp 2-7. All transfer products were isolated from the reaction mixtures by HPLC and their structures established by electrospray mass spectrometry and 1H and 13C NMR spectroscopy. The glycosides synthesised, beta-Xyl-1-->(4-beta-Xyl-1-->)(n)4-beta-Xyl-OC6H4NO2-p (n=1-5), were tested as chromogenic substrates for family 10 beta-xylanase from Aspergillus orizae (XynA) and family 11 beta-xylanase I from Trichoderma reesei (XynT) by reversed-phase HPLC and UV-spectroscopy techniques. The action pattern of XynA against the foregoing PNP beta-(1-->4)-D-xylooligosaccharides differed from that of XynT in that the latter released PNP mainly from short PNP xylosides (dp 2-3) while the former liberated PNP from the entire set of substrates synthesised.
authors.affiliation: Petersburg Nuclear Physics Institute, Russian Academy of Science, Molecular and Radiation Biology Division, Gatchina, 188350, St. Petersburg, Russia.
authors.forename: Elena V
authors.initials: EV
authors.lastname: Eneyskaya
authors.forename: Harry
authors.initials: H
authors.lastname: Brumer
authors.forename: Leon V
authors.initials: LV
authors.lastname: Backinowsky
authors.forename: Dina R
authors.initials: DR
authors.lastname: Ivanen
authors.forename: Anna A
authors.initials: AA
authors.lastname: Kulminskaya
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Shabalin
authors.forename: Kirill N
authors.initials: KN
authors.lastname: Neustroev
mesh_terms: D001230:Aspergillus / Q000201:enzymology*; D002851:Chromatography, High Pressure Liquid; D002863:Chromogenic Compounds / Q000138:chemical synthesis*; D006027:Glycosides / Q000138:chemical synthesis; D006031:Glycosylation; D009844:Oligosaccharides / Q000138:chemical synthesis; D013057:Spectrum Analysis; D043325:Xylan Endo-1,3-beta-Xylosidase; D014994:Xylose; D014995:Xylosidases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D002863:Chromogenic Compounds; D006027:Glycosides; D009844:Oligosaccharides; D014994:Xylose; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase; C026579:exo-1,4-beta-D-xylosidase