摘要
在纯化研究的基础上对土壤中筛选诱变得到的黑曲霉菌株所产的β－Ｄ甘露聚糖酶进行了部分酶学性质的研究。该酶的最适温度为５５℃，最适ｐＨ为５．５，酸碱稳定区域为４．５～８．０，以魔芋精粉和瓜儿豆胶为底物分别测得该酶米氏常数为１４．２ｇ／Ｌ，１０．２ｇ／Ｌ，发现Ａｇ＋、Ｐｂ２＋离子对该酶有较强的抑制作用，Ｃａ２＋离子有一定的激活作用。纯化酶的氨基酸组成分析表明，天门冬氨酸和谷氨酸（包括酰胺）含量为２６．９％．利用纸层析初步了解了不同条件下粗酶对魔芋精粉底物的水解产物情况。
After a β D mannanase had been purified from Aspergillus niger , we studied the enzymic properties and chemical composition of this enzyme. The optimum pH was found to be 5.5 (stable from 4.5￣8.0) and the optimum temperature 55 ℃. The enzyme followed typical Michaelis Menten kinetics with apparent Km of 14.2 g/L and 10.2 g/L for konjak powder and Guar gum. Effects of various metal ions and buffers on enzyme activity were also examined.The activity of enzyme was enhanced by Ca 2+ ,but strongly inhibited by Pb 2+ 、Ag +. Analyses of amino acid composition showed that this β D mannanase contained about 26.9% Asx and Glx.
