论文部分内容阅读
为明确臭曲霉ZU-G1分泌的α-半乳糖苷酶的酶学性质,采用硫酸铵沉淀、分子筛层析和阴离子交换层析等方法进行分离纯化。试验结果表明:α-半乳糖苷酶的分子质量136.71kDa,反应最适pH5.0,最适温度60℃;在30～40℃环境中热稳定性较好,在pH6.0环境中酸碱稳定性较好。该酶受Ag+和十二烷基磺酸钠的强烈抑制(抑制率分别为100%和93%)、Cu2+的明显抑制,而Ca2+、Mg2+、Zn2+、Mn2+、K+、Na+、棉籽糖、乙二胺四乙酸和巯基乙醇对酶活性影响较小。该酶对pNPG的米氏常数Km=33.48mmol/L,最大反应速度Vmax=238.09mmol/(L·min)。本试验结果为α-半乳糖苷酶在饲料和食品中的应用提供了一定的理论基础。
To clarify the enzymatic properties of α-galactosidase secreted by Aspergillus foetidus ZU-G1, ammonium sulfate precipitation, molecular sieve chromatography and anion exchange chromatography were used to separate and purify α-galactosidase. The experimental results showed that the molecular weight of α-galactosidase was 136.71 kDa, the optimum reaction temperature was pH5.0, the optimum temperature was 60 ℃, and the thermostability was good in 30-40 ℃ environment. Stability is better. The enzyme was strongly inhibited by Ag + and sodium dodecyl sulfate (inhibition rates were 100% and 93%, respectively) and Cu2 + was significantly inhibited, while Ca2 +, Mg2 +, Zn2 +, Mn2 +, K +, Na +, raffinose, Amine tetraacetic acid and mercaptoethanol had little effect on enzyme activity. The Michaelis constant of the enzyme pNPG Km = 33.48mmol / L, the maximum reaction rate Vmax = 238.09mmol / (L · min). The results of this experiment provide a theoretical basis for the application of α-galactosidase in feed and food.