二价金属离子在分离大豆种子尿囊素酶中的作用  

THE ROLE OF BIVALENT CATIONS ON THE ISOLATION OF ALLANTOINASE FROM THE SOYBEAN SEED EXTRACTS

作　　者：刘承宪[1] 

机构地区：[1]中国科学院上海植物生理研究所,上海200032

出　　处：《Acta Botanica Sinica》1996年第7期505-511,共7页Acta Botanica Sinica（植物学报：英文版）

基　　金：国家自然科学基金

摘　　要：大豆 (Glycine max L.cv.Keyu 10 )种子和叶片提取液中的尿囊素酶 (ALNase)是热稳定的 ,但在Ca2 +、Mg2 +或 Mn2 +存在的条件下对热有不同的反应。 75℃热处理 5 min,种子提取液中的酶除 Mg2 +尚存有 1/ 3酶活性外 ,其余全部丧失 ,56%以上的蛋白质变性 ;叶片提取液中的酶除 Mn2 +使活性下降 36%外其余仍然稳定 ,热变性蛋白也不因 Ca2 +、Mg2 +和 Mn2 +的存在有明显增加。在室温下二价金属离子可以清除大豆种子提取液中 50 %以上非酶蛋白 ,但不影响酶活性。二价金属离子这种作用和其浓度无关 ,增加浓度反而有减弱的趋势 ,也不受 Na Cl的影响。两种 ALNase提取液对不同的难溶性钙盐也有不同的反应 ,种子提取液经 5% Ca SO4 处理后非酶蛋白减少近 50 % ,酶活性受影响不大 ;叶片提取液对Ca3 (PO4 ) 2 敏感 ,经处理后酶活性损失 50 %左右 ,蛋白损失近 70 %。 Mn2 +对种子提取液中 ALNase有激活作用 ,但这种激活作用随着酶的纯化而消失。乙二胺四乙酸钠 (EDTA)对两种提取液中 ALNase活性没有影响 ,但外加二价金属离子浓度接近Allantoinases (ALNase) in the water extracts distilled from seeds and leaves of soybean (Glycine max L.cv.Keyu 10) were remarkably heat stable.However the enzyme and non enzyme protein in the seed extract,but not leaf extract, lost their activity and were denaturated at 75℃ for 5 min in the presence of Ca 2+ ,Mg 2+ or Mn 2+ ions respecitively.At room temperature over 40%～50% of the non enzyme proteins in the seed extract could be removed by the bivalent cations without affecting the enzyme activity.This effect was weakend by the increase of concentration.Both extracts had different responses to all sorts of insoluble Ca 2+ salts.For the seed extract about 50% of the non enzyme proteins were removed by 5% CaSO 4 (W/V), without effecting the enzyme activity,while the leaf extract was sensible to Ca 3(PO 4) 2.After treatment with 5% Ca 3(PO 4) 2 about 50% of the enzyme activities and about 70% of proteins were lost.Mn 2+ ions could enhance the enzyme activity in crude seed extract,but had no effect on partially purified enzyme from seeds and enzyme in crude extract from leaves.Further,EDTA had no effect on enzyme activity in both extracts.

关 键 词：大豆 尿囊素酶 二阶阳离子 

分 类 号：S565.101[农业科学—作物学]