摘要
为了寻求大豆脲酶的国产化途径,对市售大豆进行了脲酶提取研究。用乙醇水溶液从市售大豆中提取出了大豆脲酶,测得该脲酶的Km值为3.576×10-2,1.0mL提取液的酶活力为26.58U。大豆脲酶分解尿素的产物为铵氮,借助钠氏试剂比色法和凯氏定氮法对生成的铵氮进行了比色分析,进而从乙醇浓度、固液比、pH值考察了脲酶的最佳提取条件。确定的最佳乙醇浓度为30%、固液比为1∶10,最适pH值为7.0。
The problem of lacking soybean urease in Chinese has been becoming more and more serious thanks to the increasing market demand although soybean（ Glycine max）was planted in large area all across China, the experiment was designed to extract soybean urease by ethanol-water solution in laboratory and realized the predetermined target. The Km value of the soybean urease was 3. 576×10^-2 ,the enzyme activity of 1.0 mL extracting liquid was 26.58 U. The optimum conditions of extracting soybean urease were investigated by the concentration of ethanol in water,the ratio of soybean fine powder weight to extract liquid volume （W/V） and pH value of the extract solution. Urea could be decomposed to （ NH4 ） 2 CO3 by soybean urease, and NH4^＋ could be quantitatively determinated by Nessler＇ s reagent colorimetry. The absorption value at 480 nm（ A480 ）was proportional to NH4^＋ concentration in the reaction solution, so it had linear correlation with the soybean urease activity. When the concentration of cthanol in water was 30% ,A480 showed the best value 0. 885 than those were 18%, 24% ,42% and 36%. W/V equal to 1 ： 10 was the best ratio for A480 than those were 1 ： 6,1 ： 8,1 ： 12 and 1 ： 14. Kjeldahl method was used to determine the NH4^＋ concentration at different pH values, the HCl dosage in titration operation was proportional to NH4^＋ concentration thus to manifest the soybean urease activity,the experiment result showed that 7.0 was the optimum pH value.
出处
《大豆科学》
CAS
CSCD
北大核心
2008年第4期704-707,共4页
Soybean Science
关键词
大豆
脲酶
KM
酶活
Soybean （ Glycine max）
Soybean urease
Km
Enzyme activity
作者简介
周东凯（1980-），男，硕士，研究方向为环境工程与微生物技术。E-mail：zdk1980@126．com。
通讯作者：马学良，高级实验师。E-mail：max16864566@126．com。
