中文摘要：

以拟南芥为材料,对以往黑芥子酶的提取方法和活性测定方法进行了改进,通过实验优选出最佳的提取和活性测定条件.改进后的方法提取样品量只有150mg,提取缓冲溶液1mL,离心回收上清作为酶液;3mL反应体系溶液（含0.2mmol/L黑芥子硫苷酸钾）置于1cm光路石英比色杯中,37℃条件下平衡后,向反应体系溶液中添加150μL酶液,预反应3min,而后在227nm波长下测量吸光度5min（反应时间）,计算酶活.改进后的方法取样量小,操作较为简便,适于较多样品的平行测定.

英文摘要：

An improved method of extraction and activity determination for the myrosinase were investigated and the best method was proposed as follows：150 mg sample of tissue was solubilized in 1 mL of extraction buffer.The sample was centrifuged then the supernatant was collected and used as myrosinase extract.3 mL reaction mixture which contains 0.2 mmol/L sinigrin was allowed to equilibrate at 37℃ then the reaction was initiated by adding 150 μL enzyme extract to the 1cm cuvette.Decline in optical density as a result of sinigrin breakdown was plotted at 227 nm for 5 min after a 3 min pre-reaction period using a spectrophotometer.The improved method was performed by using less plant sample quantity and easy to operate,which is suitable for parallel determination of many samples.