摘要
南欧紫荆萌发种子的提取液，经硫酸铵分级沉淀，ＤＥＡＥ－纤维素柱层析，Ｂｉｏ－ＧｅｌＰ－６０和ＳｅｐｈａｄｅｘＧ－１００柱层析，得到了酶活为９８．６μ／ｍｇ的甘露聚糖酶。柱层析和聚丙烯酰胺凝胶电泳均表明其为均一性物质。南欧紫荆甘露聚糖酶由两个分子量为２万的相同亚基组成，可将以甘露聚糖为主链的多种半纤维素水解为含４～６个单糖残基的寡糖片断。它的最适ｐＨ为５，最适温度为３７℃。Ｚｎ￣２＋对该酶活性有强烈的激活作用，Ｃｕ￣２＋和Ｍｎ￣２＋则为这种甘露聚糖酶的竞争性抑制剂。动力学性质研究表明酶的活性明显地依赖于底物浓度，且只有一个活性中心。南欧紫荆甘露聚糖酶的作用方式为专一性地内切水解以β－（１→４）键连接的甘露聚糖。
A mannanase was separated and purified by ammonium sulfate fraction and chromatographies on DEAE-cellucose and Bio-Gel p-60 and Sephadex G-100 from buffer extraction of germinating Cercis Siliquastrum L. seeds. The purified Mannanase was found to behomogeneous on disc electrophoresis and gel chromatography. The optimum activity for theenzyme was found to be PH 5 and 37'℃. It consists of two subunits whose molecular weightwas 20, 000. It can degraded most D-mannan into manno-oligo-saccharides of d. p. 4-6 andmixed D-mannose oligosaccharides containing other sugar residues. Zn￣2+ has great effect onthe increase of enzyme activity. Cu￣2+ and Mn￣2+ were competitive inhibitors on the activity ofthe mannanase. The kinetic study of the mannanase indicated that it only has a active site,its activity obviously depended on the concentration of substrate, its action mode was to specially endo-hydrolyse β(1→4) linked mannan
出处
《安徽大学学报（自然科学版）》
CAS
1995年第3期81-88,共8页
Journal of Anhui University(Natural Science Edition)
关键词
紫荆
甘露聚糖酶
甘露聚糖
种子
分离
纯化
水解
Cercis siliquastrum L. mannanase
mannan
galactoglucomannan
kinetic study.
