Vrsanská M, Hirsch J, Kovác P, Biely P
Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Czechoslovakia.
Carbohydr Res. 1990 Oct 10;206(2):251-6. doi: 10.1016/0008-6215(90)80064-a.
The substrate specificity of an endo-(1----4)-beta-D-xylanase of the yeast Cryptococcus albidus was investigated using a series of methyl beta-D-xylotriosides. In addition to (1----4) linkages, the enzyme could cleave (1----3) and (1----2) linkages adjacent to a (1----4) linkage and further from the non-reducing end of the substrate. The enzyme could hydrolyse a (1----3) linkage that attached a terminal xylopyranosyl group to a (1----4)-linked xylobiosyl moiety. The enzyme did not attack alpha-D-xylosidic linkages. The rate of cleavage of (1----4) linkages was much higher than those of other linkages at 0.5mM substrate, but the rates were comparable at 20mM substrate when transglycosylation reactions also occurred that facilitated degradation of the substrates.
利用一系列甲基β-D-木三糖苷研究了酵母白假丝酵母的一种内切（1→4）-β-D-木聚糖酶的底物特异性。除了（1→4）键外，该酶还可以切割与（1→4）键相邻且远离底物非还原端的（1→3）和（1→2）键。该酶可以水解将末端木吡喃糖基连接到（1→4）连接的木二糖部分的（1→3）键。该酶不攻击α-D-木糖苷键。在0.5mM底物浓度下，（1→4）键的切割速率远高于其他键，但在20mM底物浓度下，当发生转糖基化反应促进底物降解时，各键的切割速率相当。
