苜蓿种子萌发过程中二胺氧化酶活性的变化

Changes of Diamine Oxidase Activity in Alfalfa Seeds During Germination

研究苜蓿种子不同生长条件、不同生长时期及不同器官二胺氧化酶(DAO)活性的变化.结果表明:(1)黑暗条件下生长的苜蓿黄化苗的酶活性(35.38nKat)明显高于光照条件下生长的绿苗的酶活性(8.89nKat);(2)浸泡24h后的种子中均未测出DAO,第3d时DAO活性达到最高点33.06nKat,其后酶活性开始下降,培养至第7d酶活性与发芽之初接近;(3)对苜蓿幼苗不同器官进行酶活性测定,下胚轴(78.91nKat)>根(24.82nKat)>子叶(16.73nKat).对DAO进行分离纯化时选活性较高的黑暗培养3d的黄化苗,DAO活性主要集中在萌发初期的下胚轴处.依次用葡聚糖凝胶G-100(sephadex G-100)、DEAE-纤维素以及羟基磷灰石(hydroxyapatite)层析柱进行分离纯化,酶活性、蛋白质含量、回收率均降低.

The changes of DAO activity of alfalfa seeds under different growth conditions,different growth stages and different organs were studied.The results showed that：（1）Enzyme activity（35.38 nKat）of alfalfa seedlings grown under dark conditions was significantly higher than that of green seedlings（8.89 nKat）under light conditions.（2）DAO was not detected in the seeds after 24 hours of immersion.The activity of DAO reached the highest point 33.06 nKat at the third day,then the activity of the enzyme began to decline.The activity of the enzyme was close to the beginning of germination at the seventh day.（3）We measured the enzymatic activities of different organs of alfalfa seedlings.The test results were hypocotyls（78.91 nKat）〉root（24.82 nKat）〉 cotyledons（16.73 nKat）.The activity of DAO was mainly concentrated on the hypocotyls of the early germination stage when the DAO was isolated and purified from the yellow seedlings which was cultivated at darkness for 3 days had higher activity.In addition,G-100,DEAE-cellulose and hydroxyapatite chromatography were used to separate and purify the enzyme activity,protein content and recovery rate.