樟子松外生菌根中NADP-依赖型异柠檬酸脱氢酶的酶学性质研究  

Enzymatic Characterization of NADP-dependent Isocitrate Dehydrogenization in Pinus sylvestris var. mongolica Ectomycorrhiza

作　　者：王一超[1] 姚庆智[1] 朱和平[1] 陈丽霞[1] 郭欣[1] 杨倩倩[1] 闫伟[1] 

机构地区：[1]内蒙古农业大学生命科学学院,呼和浩特010018

出　　处：《生物技术通报》2015年第8期114-118,共5页Biotechnology Bulletin

基　　金：内蒙古自治区自然科学基金项目(2012MS0509)

摘　　要：对褐环乳牛肝菌-樟子松菌根组织、樟子松根组织及褐环乳牛肝菌纯培养菌丝的异柠檬酸脱氢酶(isocitrate dehydrogenase,IDH)进行纯化和酶学性质鉴定。通过硫酸铵分级沉淀及葡聚糖凝胶层析纯化后的IDH进行SDS-PAGE电泳检测,并进行3种来源酶的酶学性质鉴定。菌根组织、根组织及真菌纯培养菌丝NADP-IDH对NADP+的Km值分别为10.7μmol/L、11.4μmol/L和22.1μmol/L;对异柠檬酸的Km值分别为71.7μmol/L、79.3μmol/L和87.8μmol/L。最适p H分别为8.2、8.0和7.5,略偏碱性。菌根IDH和根IDH的最适反应温度为45℃,真菌IDH的最适反应温度为42℃。3种IDH的活性依赖于不同的二价金属阳离子的存在,Mn2+、Mg2+存在时酶活性最强,Ca2+、Co2+、Cu2+和Zn2+对酶的活性有较强抑制作用。菌根真菌与樟子松形成外生菌根之后异柠檬酸脱氢酶的蛋白含量及酶活力都得到了提高。The purpose of the work is to purify the isocitrate dehydrogenase （ IDH ） in mycorrhizal tissue of Suillus lutetts-Pinus sylvestris var. mongolica, root tissue of P. sylvestris vat. mongolica and cultured fungal mycelia of S. luteus, and identify their enzymatic characterizations. The IDHs of 3 sources were purified by ammonium sulfate precipitation and glucan gel chromatography and tested by SDS- PAGE electrophoresis, and enzymatic characterizations were studied. The Km for NAI）P＋ of mycorrhiza, root and cultured fungal mycelia were 10.7μmol/L, 11.4 μmol/L and 22.1 μmol/L, respectively ; the Km for isocitrate were 71.7 μmol/L, 79.3 μmol/L and 87.8 μmol/L, respectively. The optimal pH of mycorrhiza, root and cultured fungal mycelia were 8.2, 8.0 and 7.5 respectively ; they were all slightly in alkaline. The optimal temperatures of the IDHs were 45% for mycorrhiza and root, and 42℃ for the fungus. The activities of 3 IDHs relied on the binding of divalent metal ions, the maximum activities of IDHs were observed when assayed with Mn2＋ or Mg2＋ as metal cofactor ; however, Ca2＋, Co2＋ , Cu2＋ and Zn2＋ dramatically inhibited the activity of IDHs. Conclusively, protein eontent and enzyme activity of myeorrhizal IDH have been increased.

关 键 词：樟子松 共生菌根 异柠檬酸脱氢酶 酶学性质 

分 类 号：Q936[生物学—微生物学]