双酶法水解辐照改性马铃薯淀粉动力学研究  

Kinetics of Enzymatic Hydrolysis of Irradiated Potato Starch byα-Amylase and Glucoamylase

作　　者：张喻[1,2] 谭兴和[1,2] 熊兴耀 蔡文[1,2] 苏小军[1,3] 

机构地区：[1]湖南农业大学食品科学技术学院,湖南长沙410128 [2]食品科学与生物技术湖南省重点实验室,湖南长沙410128 [3]生物质醇类燃料湖南省工程实验室,湖南长沙410128

出　　处：《激光生物学报》2013年第5期447-452,共6页Acta Laser Biology Sinica

基　　金：国家科技支撑计划项目(2007BAD41B03)

摘　　要：为了解辐照改性马铃薯淀粉的酶解特性,用α-淀粉酶和糖化酶同时作用于马铃薯原淀粉和经400 kGy剂量辐照处理后淀粉,考察了pH值、酶解温度、α-淀粉酶用量、糖化酶用量对反应速率的影响。以米氏方程为基础,用Lineweaver-Burk法求解动力学参数。结果表明,辐照后马铃薯淀粉的酶解反应速率明显高于马铃薯原淀粉。在单一水解体系中,α-淀粉酶和糖化酶对辐照前后马铃薯淀粉的降解都遵循Michaelis-Menten方程,α-淀粉酶的Km分别为11.343 mg·mL-1和9.386 mg·mL-1,Vmax分别为0.406 mg(mL·min)-1和1.079 mg(mL·min)-1;糖化酶的Km分别为10.307 mg·mL-1和8.905 mg·mL-1,Vmax分别为0.338 mg(mL·min)-1和0.821mg(mL·min)-1;水解产物葡萄糖对反应体系具有竞争性抑制剂的作用,其抑制常数Ki分别为1.298 mg·mL-1和0.934 mg·mL-1。研究结果表明辐照有效提高了马铃薯淀粉的酶解反应活性。In order to understand the enzymatic hydrolysis characteristics of irradiated potato starch,potato native starch and potato starch treated with 60Co-γ ray at dosage of 400 kGy were hydrolyzed by α-amylase and glucoamylase.The effects of pH,hydrolysis temperature and enzyme dosage on hydrolysis rate were investigated.Based on the Michaelis-Menten equation,the kinetic parameters were obtained by the Lineweaver-Burk method.The results indicated that hydrolysis rate of irradiated potato starch was obviously higher than that of native starch.Individual enzymatic hydrolysis processes obeyed the Michaelis-Menten model,and the Michaeli constant （Km） of α-amylase were 11.343 mg · mL-1 （native starch） and 9.386 mg · mL-1 （irradiated starch）,and maximum reaction velocity （Vmax） of α-amylase were 0.406 mg（mL · min）-1 （native starch） and 1.079 mg（mL · min）-1 （irradiated starch）,respectively.The Michaeli constant （Km） of glucoamylase were 10.307 mg · mL-1 （native starch） and 8.905mg · mL-1 （irradiated starch）,and maximum reaction velocity （Vmax） of glucoamylase were 0.338 mg （mL · min）-1 （native starch） and 0.821 mg（mL ·min）-1 （irradiated starch）,respectively.The hydrolysis product glucose was a competitive inhibitor against the enzymes with an inhibitory constant （Ki） of 1.298 mg · mL-1 （native starch） and 0.934 mg · mL-1 （irradiated starch）.It indicated that irradiation greatly increased enzymatic hydrolysis activity of potato starch.

关 键 词：马铃薯淀粉 辐照 α-淀粉酶用量 糖化酶 动力学 

分 类 号：S124.1[农业科学—农业基础科学] TS231[轻工技术与工程—粮食、油脂及植物蛋白工程]