51785-69-4Relevant academic research and scientific papers
Positional specificity of Flavobacterium johnsoniae acetylxylan esterase and acetyl group migration on xylan main chain
Puchart, Vladimír,Gjermansen, Morten,Mastihubová, Mária,M?rkeberg Krogh, Kristian B.R.,Biely, Peter
, (2020/01/09)
A new Flavovacterium johnsoniae isolate encodes an enzyme that is essentially identical with a recently discovered novel acetylxylan esterase, capable of liberating 3-O-acetyl group from 4-O-methyl-D-glucuronic acid-substituted xylopyranosyl (Xylp) residues (Razeq et al., 2018). In addition to deesterification of the 2-O-MeGlcA-substituted Xylp residues in acetylglucuronoxylan, the enzyme acts equally well on doubly acetylated Xylp residues from which it liberates only the 3-O-acetyl groups, leaving the 2-O-acetyl groups untouched. 3-O-Monoacetylated Xylp residues are attacked with a significantly reduced affinity. The resulting 2-O-acetylated xylan was used to investigate for the first time the migration of the 2-O-acetyl group to position 3 within the polysaccharide. In contrast to easy acetyl group migration along the monomeric xylopyranosides or non-reducing-end terminal Xylp residues of xylooligosaccharides, such a migration in the polymer required much longer heating at 100 °C. The specificity of the xylan 3-O-deacetylase was, however, no so strict on acetylated methyl and 4-nitrophenyl xylopyranosides.
Deoxy and deoxyfluoro analogues of acetylated methyl β-D- xylopyranoside - Substrates for acetylxylan esterases
Mastihubova, Maria,Biely, Peter
, p. 2101 - 2110 (2007/10/03)
Four modified substrates for acetylxylan esterases, 2-deoxy, 3-deoxy, 2-deoxy-2-fluoro, and 3-deoxy-3-fluoro derivatives of di-O-acetylated methyl β-D-xylopyranoside were synthesized via 2,3-anhydropentopyranoside precursors. Methyl 2,3-anhydro-4-O-benzyl-β-D-ribopyranoside was transformed into methyl 2,3-anhydro-4-O-benzyl-β-D-lyxopyranoside in three steps. The epoxide ring opening of 2,3-anhydropentopyranosides was accomplished either by hydride reduction or hydrofluorination. Methyl β-D-xylopyranoside 2,3,4-tri-O-, 2,4-di-O-, and 3,4-di-O-acetates, and the prepared diacetate analogues were tested as substrates of acetylxylan esterases from Schizophyllum commune and Trichoderma reesei. Measurement of their rate of deacetylation pointed to unique structural requirements of the enzymes for the substrates. The enzymes differed particularly in the requirement for the trans vicinal hydroxy group in the deacetylation at C-2 and C-3 and in the tolerance to the presence of trans vicinal acetyl groups esterifying the OH group at C-2 and C-3.
A common access to 2- and 3-substituted methyl β-D-xylopyranosides
Mastihubová, Mária,Biely, Peter
, p. 9065 - 9067 (2007/10/03)
2-Deoxy-, 3-deoxy-, 2-deoxy-2-fluoro- and 3-deoxy-3-fluoro- derivatives of methyl β-D-xylopyranoside diacetates were prepared by a new common route via 2,3-anhydropentosides. The stereo- and regioselective introduction of fluorine or hydrogen was accompli
