底物和产物对鲜切山药苯丙氨酸解氨酶活性的影响

本实验以山药为材料提取苯丙氨酸解氨酶(PAL),研究底物和产物对山药PAL活性的影响。结果表明:苯丙氨酸促进PAL活性,PAL最适底物浓度为200mg/L,底物浓度过高或过低对酶活力都不利;反式肉桂酸抑制PAL活性,最强抑制浓度为120mg/L,高于或低于这个浓度抑制作用减弱;阿魏酸抑制PAL活性,最强抑制浓度为40mg/L,之后随浓度增加抑制作用减弱,浓度增加至100mg/L时抑制作用最弱,以后随浓度增加抑制作用又增强。

Effects of Substrate and Products on Activity of Phenylalanine Ammonia-lyase(PAL) in Fresh-cut Yam

The effects of substrate and terminal products on the activities of phenylalanine ammonia-lyase (PAL) in fresh-cut yam. The results showed that the optimum substrate concentration of PAL was 200 mg/L. Although concentration of phenylalanine (Phe) was higher or lower than 200 mg/L, the enzyme activities were inhibited. The trans-cinnamic acid (CA) inhibited the PAL activity, and activity was inhibited most strongly by 120 mg/L CA. Although CA was higher or lower than 120 mg/L, the inhibition decreased. The ferulic acid(FA) inhibited the PAL activity, and effects of 40 mg/L concentration were strongest. With the concentration increased, the inhibition effects decreased. When concentration of FA was 100 mg/L, the effect of inhibition was weakest, then with the concentration increase the effects of inhibition were increased too.