摘要
从拟康氏木霉Ｔｒｉｃｈｏｄｅｒｍａ ｐｓｅｕｄｏｋｏｎｉｎｇｉｉＳ－３８菌株发酵液中分离纯化了一个外切葡聚糖纤维二糖水解酶（ＣＢＨＩ，ＣＥ３．２．１．９１）和一个内切葡聚糖酶（ＥＧＩ，ＥＣ３．２．１．４）。经木瓜蛋白酶有限酶切，分别都得到了一个对可溶性底物具有与天然酶相近活力的催化结构域位于天然酶分子的Ｃ端，圆二色谱测定表明其催人域具有与天然酶相似的结构特征。由有限酶切内。
Limited protco1ysis of an endopucanase (EG I) and an exocellobiohydrilase (CBH l)from Trichoderma psethefoedi S - 38 vielded respective1y, a catalytic dondn with similarcatalytic activity for souble sudstrate as intact enzyme, and a domain containg two short peptides,which can adsorb insoluble cellulose. The results of C - terminal sequencing suggested that thecatalytic domain of EG I may be located in N - terminal of intact enzyme, and circular dichronism(CD) studies indicated that the catalytic domain disp1ayed a similar conformational propertiescompared to that of intact enzyme. The CBH I molecule has a blocked N - terminal and containedabout 12% of carboydrite,while the carbohydrite of CBH I - core only 1. 5%. Estimate by CDshien that in intact CBH I there wes no 220 nn' s'trough', the a - helical content was alsosmall,and the positive peak at 195nm was present, while the nwtve peak at 205 - 215nm wasabsence,which indicated that the CBH I is a protein with rich B -structre. Studies as decarepH and ligaded cellobiase suggested that the spectroscopic properties of CBH I is dependent on its core.
出处
《纤维素科学与技术》
CAS
CSCD
1998年第3期1-9,共9页
Journal of Cellulose Science and Technology
基金
国家自然科学基金
国家教委博士点基金
关键词
纤维素酶
葡聚糖酶
有限酶切
结构域
水解酶
cellulase, endoglucanase, exocellobiohydrolase,proteolysis,domain
