摘要
地衣芽孢杆菌（Ｂａｃｉｌｌｕｓｌｉｃｈｅｎｉｆｏｒｍｉｓ）ＮＫ－２７菌株发酵产生的β－甘露聚糖酶（β－ｍａｎｎａｎａｓｅ）经硫酸铵盐析沉淀，两次ＤＥＡＥ纤维素和ＳｅｐｈａｄｅｘＧ－１００离子交换柱层析以及制备ＰＡＧＥ筹步骤，获得了凝胶电泳均一的样品。用ＳＤＳ－凝胶电泳测得纯化后的β－甘露聚糖酶分子量为２６ｋＤ，用凝胶聚焦电泳测得等电点ＰＩ为５．０。酶反应的最适ｐＨ为９．０，最后温度为６０℃，稳定ｐＨ为６．０—９．０，稳定温度为４０℃。金属离子中Ｍｇ￣（２＋）、Ｃａ￣（２＋）、Ｆｅ￣（２＋）、Ｎｉ￣（２＋）对该酶有一定的激活作用；而Ｓｎ￣（２＋）、Ｚｎ￣（２＋）、Ａｌ￣（３＋）、Ａｇ￣＋和Ｈｇ￣（２＋）对该酶有强烈的抑制作用。ＮＫ－２７菌株的β－甘露聚糖酶对魔芋葡萄甘露聚糖和角豆胶半乳甘露聚糖的Ｋｍ值分别为７．１４和５．５６ｍｇ·ｍｌ￣（－１）；Ｖ＿（ｍａｘ）分别为２００．５３和１５７．４５μｍｏｌ·ｍｇ￣（－１）·ｍｉｎ￣（－１）。
The β-mannanase was yield by Bacillus licheniformis Nk-27 the β-mannanasewas purfied to SDS-PAGE homogeneity by(NH_4)_2SO_4 precipita tion,twice DEAE-Cellulosecolumn chromatography, Sephadex G-100 column gel filtration.Molecular weight and Pevalues of the β-mannanase were 26000 and 5.0 by SDS-PAGE and PAGEIEF.The optimumconditions for enzyme activity were pH9.0,temperature 60℃.Its showed a high stability attemperature 40℃.The activity of enzyme were enhanced by Mg￣(2+),Ca￣(2+),Fe￣(2+),Ni￣(2+),and were stronglyinhibited by Sn￣(2+),Zn￣(2+),Al￣(3+),Ag￣+,Hg￣(2+)。The michaelis constants(Km)values for Konjak-glucomannan and locust bean-galactomannan were 7.14mg/ml and 5.56mg/ml.Maximunvelocities(V_max) for saccharides were 200.53μmol·mg￣(-1)· min￣(-1)and 157.45 μmol·mg￣(-1)·min￣(-1).
出处
《微生物学通报》
CAS
CSCD
北大核心
1995年第6期338-342,共5页
Microbiology China
基金
南开大学科学发展基金
