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投稿时间：2015-05-28
投稿时间：2015-05-28
中文摘要: 以新鲜南国梨果实为原料，邻苯二酚为底物，采用分光光度法研究南国梨多酚氧化酶的酶学特性。结果表明：pH和温度对新鲜南国梨PPO活性有明显的影响，最适pH为6.8，新鲜南国梨PPO最适温度为40℃。进一步研究了抑制剂抗坏血酸、柠檬酸、亚硫酸氢钠、L-半胱氨酸、EDTA-2Na和各种金属盐 [CuSO4、CaCl2、Na2SO4、Al（NO3）3、CdCl2、HgCl2、MnCl2]对南国梨PPO的影响，其中0.1 mmol/L的抗坏血酸对新鲜南国梨PPO活性有明显抑制作用高达50%。南国梨PPO催化底物邻苯二酚的酶促反应动力学与米氏方程高度符合，R2=0.998，其动力学方程为1/[V]=0.002/[S]+0.019，最大反应速率Vmax为52.632 U/min，米氏常数Km为0.010 5 mol/L。
Abstract:Fresh Nanguo pear as raw material，catechol as substrate，using spectrophotometric study of southern pear enzymatic characteristics of polyphenol oxidase.The results showed that：p H and temperature had a significant effect on fresh Nanguo pear PPO activity and the optimum pH was 6.8，fresh pear PPO optimum temperature was 40℃.Further study of the inhibitor of ascorbic acid，citric acid，sodium bisulfite，L-cysteine，EDTA-2Na and various metal salts[CuSO4，CaCl2，Na2SO4，Al（NO3）3，CdCl2，HgCl2，MnCl2]effectof southern pear PPO，where 0.1 mmol/L of ascorbic acid on fresh pear PPO activity was sign if icantly inhibited by up to 50%.Nanguo pear PPO enzymatic catalytic substrate catechol reaction kinetics and the Michaelis-Menten equation height accord，R2=0.998，its kinetic equation 1/[V]=0.002/[S]+0.019，maximum reaction rate Vmaxto 52.632 U/min，the Michaelis constant Kmof0.010 5 mol/L.
文章编号：201612008 中图分类号： 文献标志码：
基金项目:
| Author Name | Affiliation |
| HE Xiao-meng，KONG Fan-dong | College of Food Science，Dalian Polytechnic University，Dalian 116000，Liaoning，China |
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