【摘要】 目的研究低聚果糖产生菌黑曲霉 (Aspergillusniger)SIPI 6 0 2来源的 β 果糖基转移酶 (β FT)的性质。 方法经典的酶学研究方法。结果 β FT催化蔗糖转化成蔗果三糖的Km和Vmax分别为 2 6 8.37g L和 2 .37g (min·L) ;将蔗果三糖转化成蔗果四糖的Km和Vmax分别为 173.0 8g L和 0 .10g (min·L)。葡萄糖是 β FT的竞争性抑制剂 ,其Ki=2 4 5 .2 3g L。β FT反应的最适pH为 4 .5～ 6 .0 ,最适温度为 5 5℃。β FT在中性条件、5 0℃以下稳定性良好。β FT转化蔗糖生成低聚果糖的反应进程实验表明 ,高浓度的底物有利于提高反应速度和转化率 ,并且产物中果糖浓度较低浓度底物中低。结论黑曲霉SIPI 6 0 2来源的 β FT适合用于工业化生产低聚果糖更多还原

【Abstract】 PurposeTo investigate the properties of β-fructosyltransferase(β-FT) from Aspergillus niger SIPI-602.MethodsWith classic enzyme methodology.ResultsThe Km and Vmax values of β-FT for sucrose were 268.37 g/L和2.37 g/min/L by using the Lineweaver-Burk plot, respectively and the Km and Vmax values of β-FT using GF 2 as a substrate were 173.08 g/L和0.10 g/min/L. Glucose was a competitive inhibitor and it’s Ki=245.23 g/L. The optimum pH and temperature of β-FT were 4.5～6.0 and 55℃ respectively. β-FT was stable up to 50℃ at pH 5.8 for one hour of incubation and from pH6.0 to 8.0 at 40℃ in one hour of incubation. The time-course of the formation of fructooligosaccharides from sucrose indicated that the reaction rates increased at a high initial sucrose concentration and the fructose concentration in the product was lower than that at a comparatively low sucrose concentration.ConclusionThis enzyme was suitable for industrial production of fructooligosaccharides.更多还原