论文部分内容阅读
经硫酸铵分级沉淀、SephadexG-100凝胶过滤层析纯化,得到部分纯化的胡萝卜过氧化物酶(POD)和苯丙氨酸解氨酶(PAL)。这两种酶的纯化倍数分别为7.44倍和5.87倍,回收率分别为32.51%和5.06%。酶学性质和动力学性质研究表明,胡萝卜POD和PAL的最适pH分别为5.0和8.4;在不同pH值下POD和PAL的活力及其耐受性变化趋势相似。POD的适宜温度为30℃,当温度40～50℃时,PAL酶活力达到最高点。PAL酶液体积为1.6mL时,反应速度最快;而POD酶液体积分别为1.0mL和1.6mL时,反应速度出现峰值。当POD和PAL底物浓度分别为44.8×10-6mol/L和0.02mol/L时,反应速度达到最大值。Na+、10mmol/LCa2+、0.1mmol/LNH4+、Mg2+可以同时显著地(P<0.05)抑制胡萝卜POD和PAL酶的活力。胡萝卜POD与愈创木酚的亲合力强,PAL与L-苯丙氨酸的亲合力较小。
The fractions were precipitated with ammonium sulfate and purified by Sephadex G-100 gel filtration chromatography to obtain partially purified POD and PAL. The purification rates of these two enzymes were 7.44 and 5.87 times, respectively, and the recoveries were 32.51% and 5.06%, respectively. The results of enzymatic and kinetic studies showed that the optimal pH values of POD and PAL for carrot were 5.0 and 8.4, respectively. The changes of viability and tolerability of POD and PAL were similar at different pH values. The optimum temperature of POD is 30 ℃. When the temperature is 40 ~ 50 ℃, the activity of PAL reaches the highest point. When the volume of PAL enzyme solution was 1.6mL, the reaction rate was the fastest; when the volume of POD enzyme solution was 1.0mL and 1.6mL, the reaction speed peaked. When the POD and PAL substrate concentrations were 44.8 × 10-6mol / L and 0.02mol / L, the reaction rate reached its maximum. Na +, 10mmol / L NaH2 +, 0.1mmol / LNH4 + and Mg2 + could significantly (P <0.05) inhibit the activity of POD and PAL enzyme in carrot simultaneously. Carrot POD and guaiacol affinity strong, PAL and L-phenylalanine affinity less.