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Study on a new aminopeptidase from hen's egg

一种新型鸡蛋氨肽酶的研究

基本信息

批准号：
62560075
负责人：
ICHISHIMA Eiji
金额：
$ 1.28万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

An aminopeptidase Ey is a newly discovered enzyme of hen's egg yolk. about 95 % of the total activity was found in the yolk plasma fraction,with the most remainder in the yolk granule fraction. The highly purified fraction from plasma showed about 13,000-folds higher spcific activities than that of yolk plasma. Polyacrylamide gel electrophoresis revealed that the enzyme was homogeneous. The bound enzyme in the granule was extracted with 3 % NaCl and was partially purified. The soluble and bound forms of aminopeptidase differ in solubility, molecular weight, heat stability, optimal pH and Km. The molecular weight determination with gel filtration on Toyo-pearl HWs indicated that the values of the aminopeptidase Eyp from plasma and Eyg from granule were 360,000 and 700,000, respectively. The Km value for L-MCA at pH 6.5 of the aminopeptidase Eyp from plasma fraction was determined to be 0.01 ml, while the km value of Eyg from granule fraction was 0.8 mM at pH 7.5. The aminopeptidase Eyp was stable between 30 and 50 ゜C for 10 min at pH 7.5 and 30゜C, while the aminopeptidase Eyg was activated with increasing temperature from 30 to 60 ゜C. The metal requirement suggests that the soluble aminopeptidase from plasma, Eyp, is similar to aminopeptidase Co from the yeast Saccharomyces cerevisiae.

氨肽酶 Ey 是一种新发现的鸡蛋黄酶。约95%的总活性存在于卵黄浆部分，其余大部分存在于蛋黄颗粒部分。来自血浆的高度纯化的级分显示出比卵黄血浆高约 13,000 倍的特异性活性。聚丙烯酰胺凝胶电泳表明该酶是均质的。用 3% NaCl 提取颗粒中结合的酶并进行部分纯化。可溶形式和结合形式的氨肽酶在溶解度、分子量、热稳定性、最佳 pH 值和 Km 方面有所不同。在 Toyo-pearl HW 上通过凝胶过滤测定分子量表明，血浆中的氨肽酶 Eyp 和颗粒中的 Eyg 值分别为 360,000 和 700,000。来自血浆级分的氨肽酶Eyp在pH 6.5下的L-MCA的Km值为0.01ml，而来自颗粒级分的Eyg在pH 7.5下的Km值为0.8mM。氨肽酶Eyp在pH 7.5和30℃下在30至50℃之间稳定10分钟，而氨肽酶Eyg随着温度从30℃升高至60℃而被激活。金属需求表明血浆中的可溶性氨肽酶 Eyp 与酿酒酵母中的氨肽酶 Co 相似。