Hecker L I, Sussman A S
J Bacteriol. 1973 Aug;115(2):582-91. doi: 10.1128/jb.115.2.582-591.1973.
Trehalases from the ascospores of Neurospora tetrasperma and the mycelium of N. crassa were compared. Enzymes from both sources have identical electrophoretic mobilities, K(m)'s, responses to pH, immunological reactions, and activities in low-molarity buffers. Because both enzymes are so similar, conclusions about the properties of the ascospore enzyme may, be made by studying mycelial trehalase. Mycelial trehalase is most active and stable in low-molarity buffers. The enzyme exists in at least three species; the smallest has a molecular weight between 105,000 and 125,000 and is predominant in low-molarity buffers at 37 C. The stability of trehalase to heating at 65 C can be increased by increasing enzyme concentration and by the addition of polyols. Ascospores contain large amounts of trehalose, which protects trehalase from heat inactivation at 65 C. The importance of this phenomenon in vivo and its relationship to the localization of trehalase in ascospores is discussed.
对来自四孢脉孢菌子囊孢子和粗糙脉孢菌菌丝体的海藻糖酶进行了比较。来自这两种来源的酶具有相同的电泳迁移率、米氏常数、对pH的响应、免疫反应以及在低摩尔浓度缓冲液中的活性。由于这两种酶非常相似，因此可以通过研究菌丝体海藻糖酶来得出关于子囊孢子酶特性的结论。菌丝体海藻糖酶在低摩尔浓度缓冲液中活性最高且最稳定。该酶至少以三种形式存在；最小的一种分子量在105,000至125,000之间，在37℃的低摩尔浓度缓冲液中占主导地位。通过增加酶浓度和添加多元醇，可以提高海藻糖酶在65℃加热时的稳定性。子囊孢子含有大量海藻糖，这可保护海藻糖酶在65℃时不被热失活。本文讨论了这一现象在体内的重要性及其与海藻糖酶在子囊孢子中定位的关系。
