Action of acetylxylan esterase from Trichoderma reesei on acetylated methyl glycosides

FEBS Letters

Kremnický, L³  Côté, G.L¹  Tenkanen, M²  Biely, P³  Greene, R.V¹ 

[1] Biopolymer Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, United States Department of Agriculture, Peoria, IL 61604, USA;VTT Biotechnology and Food Research, FIN-02044 Espoo, Finland;Institute of Chemistry, Slovak Academy of Sciences, 84238 Bratislava, Slovakia

关键词: Acetylxylan esterase;    Substrate specificity;    Acetylated methyl glycoside;    Mode of action;    Trichoderma reesei;    AcXE;    acetylxylan esterase;    2;    3;    4-tri-O-Ac-Me-β-Xylp;    methyl 2;    3;    4-tri-O-acetyl-β-d-xylopyranoside;    2;    3;    4;    6-tetra-O-Ac-Me-β-Glcp;    methyl 2;    3;    4;    6-tetra-O-acetyl-β-d-glucopyranoside;    2;    3;    4;    6-tetra-O-Ac-Me-β-Manp;    methyl 2;    3;    4;    6-tetra-O-acetyl-β-d-mannopyranoside;   

DOI  :  10.1016/S0014-5793(97)01500-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Substrate specificity of purified acetylxylan esterase (AcXE) from Trichoderma reesei was investigated on partially and fully acetylated methyl glycopyranosides. Methyl 2,3,4-tri-O-acetyl-β-d-xylopyranoside was deacetylated at positions 2 and 3, yielding methyl 4-O-acetyl-β-d-xylopyranoside in almost 90% yield. Methyl 2,3-di-O-acetyl β-d-xylopyranoside was deacetylated at a rate similar to the fully acetylated derivative. The other two diacetates (2,4- and 3,4-), which have a free hydroxyl group at either position 3 or 2, were deacetylated one order of magnitude more rapidly. Thus the second acetyl group is rapidly released from position 3 or 2 after the first acetyl group is removed from position 2 or 3. The results strongly imply that in degradation of partially acetylated β-1,4-linked xylans, the enzyme deacetylates monoacetylated xylopyranosyl residues more readily than di-O-acetylated residues. The T. reesei AcXE attacked acetylated methyl β-d-glucopyranosides and β-d-mannopyranosides in a manner similar to the xylopyranosides.

【 授权许可】

Unknown