摘要
米曲霉（Ａｓｐｅｒｇｉｌｌｕｓｏｒｙｚａｅ）Ａ－９００５菌株的麸曲培养物，经水浸泡抽提其酸性蛋白酶活力为６０００ｕ／ｇ左右。硫酸铵分段沉淀中，饱和度为７０％，８０％和９０％时沉淀的比活最高，得率在７０％以上，该酸性蛋白酶的最适作用温度为５０℃，最适ｐＨ为３．５～４．７．在ｐＨ３．５～５．５时酶活力稳定，ｐＨ超过６时酶活力迅速丧失。在４０～６０℃下该酶的活力相对稳定，在７０℃下酶活力半衰期仍达７４ｍｉｎ，这一结果表明该酶为一耐热性酶种。Ｍｎ^（２＋）对酶有激活作用，其它多数金属离子如Ｚｎ^（２＋），Ｆｅ^（２＋），Ｋ~＋，Ｍｇ^（２＋），Ｌｉ~＋及Ｃａ^（２＋）等对酶有轻度抑制作用或无影响。
An acid proteinase was obtained from Aspergillus oryzae strain A-9005 cultured in wheat bran medium. The enzyme activty was about 6000u/g. The enzyme was partially purified by ammonium sulfate fractionation. The results showed that high relative activity enzyme could be obtained with ammonium sulfate of 70%, 80% and 90% in saturation. The optinium temperature and pH were 50℃ and 3. 5￣4. 7 respectively. The enzyme was rather stable at pH 3.5￣ 5.5 and at 40￣60℃. Under heat treatment at 70℃ for 74min.50% of the enzyme activity still remauied. The enzyme was activited by Mn￣(2+).while Zn￣(2+). Fe￣(2+).K￣+, Mg￣(2+). Li￣+ and Ca2+slightly inhabited its activity.
出处
《湖南师范大学自然科学学报》
1995年第3期80-84,共5页
Journal of Natural Science of Hunan Normal University
