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以曹州木瓜果实为试验材料,采用分光光度法对曹州木瓜过氧化物酶(POD)的酶学特性进行研究,为控制木瓜加工贮藏过程中的酶促褐变提供理论依据。试验结果表明:曹州木瓜POD的最适pH 5.8,最适反应温度45℃,90℃处理75 s或者100℃处理30 s后POD活性完全丧失。其过氧化物酶催化的酶促褐变反应动力学符合米氏方程,动力学参数Km=18.17 mmol/L,Vmax=1 666.67 U。抑制剂对POD的抑制作用从大到小依次为VC>亚硫酸氢钠>柠檬酸>EDTA-2Na。Na+,K+,Mg2+,Mn2+和Ca2+对POD具有激活作用,Zn2+,Ba2+和Cu2+在低浓度时对POD有激活作用,高浓度时有抑制作用。
The papaya fruits of Caozhou were used as experimental materials to study the enzymatic characteristics of papaya peroxidase (POD) by spectrophotometry, which provided a theoretical basis for the control of enzymatic browning during processing and storage of papaya. The results showed that the optimum pH of POD was 5.8, the optimal reaction temperature was 45 ℃, the activity of POD was completely lost when treated at 90 ℃ for 75 s or 100 ℃ for 30 s. The peroxidase catalyzed enzymatic browning reaction kinetics consistent with the Mie equation, kinetic parameters Km = 18.17 mmol / L, Vmax = 1 666.67 U. Inhibition of POD inhibition from descending order of VC> sodium bisulfite> citric acid> EDTA-2Na. Na +, K +, Mg2 +, Mn2 + and Ca2 + activated POD. Zn2 +, Ba2 + and Cu2 + activated POD at low concentration and inhibited at high concentration.