Specific xyloglucanases as a new class of polysaccharide-degrading enzymes
Specific xyloglucanases as a new class of polysaccharide-degrading enzymes
复制标题
DOI：
10.1016/j.bbagen.2004.07.001
复制
发表时间：
2004-11-01
影响因子：
3
通讯作者：
Sinitsyn, AP
中科院分区：
文献类型：
--
作者：
Grishutin, SG;Gusakov, AV;Sinitsyn, AP
从赤霉菌（32 kDa，pI 2.8）、路克瑙金孢菌（78 kDa，pI 3.8）和里氏木霉（75-105 kDa，pI 4.1-4.3）中分离到3种特异性木葡聚糖酶（XG）。这些酶的特征是它们对罗望子木葡聚糖的高比活性，而对羧甲基纤维素（CMC）和大麦β-葡聚糖的活性不存在或非常低。使用MALDI-TOF质谱法的肽质量指纹图谱显示，里氏木霉XG代表Ce 174 A，其基因最近已被发现（GenBank登录号AY 281371），但该酶尚未在别处表征和描述。A. C. lucknowense和C. lucknowense木葡聚糖酶没有显示出与来自已知糖苷水解酶的那些木葡聚糖酶的任何同一性。所有酶都产生XXXG、XXLG/XLXG和XLLG寡糖作为木葡聚糖水解的终产物。A.当主链中含有四个葡萄糖残基的寡糖从木葡聚糖分子的末端分裂出来时，BXG显示出对聚合物底物的内切型攻击，而另外两种木葡聚糖酶的作用模式与外切型相似。这些结果与越来越多的文献数据一起允许得出结论，特定的木葡聚糖酶可能代表一类新的糖苷水解酶，其不同于常规的内切-1，4-β-葡聚糖酶。(C)2004 Elsevier B. V.保留所有权利。
Three specific xyloglucanases (XGs) were isolated from Aspergillusjaponicus (32 kDa, pI 2.8), Chrysosporium lucknowense (78 kDa, pI 3.8) and Trichoderma reesei (75-105 kDa, pI 4.1-4.3). The characteristic feature of these enzymes was their high specific activity toward tamarind xyloglucan, whereas the activity against carboxymethy1cellulose (CMC) and barley p-glucan was absent or very low. Peptide mass fingerprinting using MALDI-TOF mass spectrometry showed that the T reesei XG represents Ce174A, whose gene has been discovered recently (GenBank accession no. AY281371), but the enzyme has not been characterized and described elsewhere. Tryptic peptides from A. japonicus and C lucknowense xyloglucanases did not show any identity to those from known glycoside hydrolases. All enzymes produced XXXG, XXLG/XLXG and XLLG oligosaccharides as the end products of xyloglucan hydrolysis. A. japonicus XG displayed an endo-type of attack on the polymeric substrate, while the mode of action of two other xyloglucanases was similar to the exo-type, when oligosaccharides containing four glucose residues in the main chain were split off the ends of xyloglucan molecules. These results together with growing literature data allow concluding that specific xyloglucanases may represent a new class of glycoside hydrolases, which are different from regular endo-1,4-beta-glucanases. (C) 2004 Elsevier B.V. All rights reserved.