摘要
从双孢蘑菇中提取酪氨酸酶，探索一种新的酪氨酸酶活力测定方法，并研究了该酶的特性及几种抑制剂对酪氨酸酶的影响。结果表明：①以L-酪氨酸为底物，在波长317nm处测定酪氨酸酶的活力，与传统习惯上所用的475nm波长相比，灵敏度高。②动力学研究显示，以L-酪氨酸为底物时，Km=0．493mmol/L，Vmax=37．88U／min。③双孢蘑菇中酪氨酸酶的最适pH值为6．5，pH值在5～7时，酶的活力较高；最适反应温度为30℃，在20～50℃范围内酪氨酸酶保持较高的活力。④抑制双孢蘑菇中酪氨酸酶活力以异抗坏血酸效果最好，当其浓度达到0．025mmol／L时能使酪氨酸酶完全失活；苯甲酸和柠檬酸的抑制效果也较好，当浓度分别达到0．060mmol／L和0．600mmol/L时也能使酪氨酸酶完全失活。
A novel method for determination of tyrosinase activity extracted from mushrooms was developed, and characteristics and effects of inhibitors were also investigated. The results showed that 1.L-tyrosine appeared higher sensitivity which was showed by the increase of absorbance at 317 nm of wavelength than that determined at 475 nm ;2.The values of Km and Vmax were 0. 493 mnol/L and 37. 88 U/min with tyrosinase as substrate;3.The optimum pH and temperature for tyrosinase to function were 6.5 and 30℃, and the enzyme activity was high at pH 5 - 7 and 20 - 50 ℃ ;4.Among all the inhibitors, erythorbic acid exhibited the strongest inhibition effect, completely inhibiting the tyrosinase activity at concentration of 0. 025 mmol/L. Benzoic acid and citric acid also completely inhibited the tyrosinase activity at concentrations of 0. 060 mmol/L and 0. 600 mmol/L in the system, respectively.
出处
《江苏农业学报》
CSCD
北大核心
2008年第2期194-198,共5页
Jiangsu Journal of Agricultural Sciences
关键词
双孢蘑菇
酪氨酸酶
特性
Agaricus bisporus
tyrosinase
characteristic
