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从一株海洋放线菌株HY-G中纯化得到了一种胞内中性β-葡萄糖苷酶。通过SDS-聚丙烯酰胺凝胶电泳和Superdex 200凝胶柱层析估计酶分子质量分别是43.3 kD和45.0 kD,两者估计值接近,表明该酶是一个单聚体,不含亚基。采用对硝基酚基-β-D-葡萄糖苷(p-NPG)做底物,测得该酶的最适pH和最适温度分别为pH 7.5和40?C。该酶在pH 6.0~7.0最稳定,在70?C保温30 min仍能保留56%的酶活力,表明具有一定的温度稳定性。基于16S rRNA基因的分类研究表明,该菌株属于拟诺卡氏菌属。 相似文献
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A superoxide dismutase was purified from Enteromorpha linza using a simple and safe procedure, which comprised phosphate buffer extraction, ammonium sulphate precipitation, ion exchange chromatography on Q-sepharose column, and gel filtration chromatography on Superdex 200 10/300GL. The E. linza superoxide dismutase (E/SOD) was purified 103.6-fold, and a yield of 19.1% and a specific activity of 1 750 U/rag protein were obtained. The SDS-PAGE exhibited E/SOD a single band near 23 kDa and the gel filtration study showed E/SOD's molecular weight is near 46 kDa in nondenatured condition, indicating it's a homodimeric protein. E/SOD is an iron-cofactored superoxide dismutase (Fe-SOD) because it was inhibited by hydrogen peroxide, insensitive to potassium cyanide. The optimal temperature for its maximal enzyme activity was 35℃, and it still had 29.8% relative activity at 0℃, then E/SOD can be classified as a cold-adapted enzyme. E/SOD was stable when temperature was below 40℃ or the pH was within the range of 5 10. The first 11 N-terminal amino acids orE/SOD were ALELKAPPYEL, comparison of its N-terminal sequence with other Fe-SOD N-terminal sequences at the same position suggests it is possibly a chloroplastic Fe-SOD. 相似文献
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研究了海洋链霉菌分离株M095的基因转移系统。利用属间接合转移将具有oriT的大肠杆菌-链霉菌穿梭质粒pIJ8600转入EscherichiacoliET12567(pUZ8002)中,获得供体菌。将供体菌与预萌发的菌株M095的孢子进行接合转移,将质粒pIJ8600转入菌株M095中,其转化率为1.99×10-4个接合转化子/受体。Southern杂交证明质粒pIJ8600已经整合到菌株M095的染色体上。同时,将来自Spirulinamaxima(Cyanophyta)的别藻蓝蛋白基因(apc)克隆在质粒pIJ8600的XbaI和BglII位点,产生质粒pAPIJ。用接合转移法将质粒pAPIJ转入菌株M095。通过SDS-PAGE分析,得到2个大小为22ku和17ku的蛋白,分别相对应于别藻蓝蛋白的α和β亚基。这些结果进一步证明菌株M095的遗传转化体系已经成功建立起来,这将为其他海洋放线菌遗传转化工作的研究奠定基础。 相似文献
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湖南省石炭系地层蕴藏着丰富的石英砂资源, 对该地层序列的研究不仅有助于深入分析石英砂形成的古地理环境特征, 而且结合构造背景的研究, 可总结石英砂成因及分布规律, 为我省硅产业发展所需原料的开发提供理论依据。为此, 本文以李畋—王仙地区石炭系地层剖面及钻孔岩芯特征为基础, 结合古地理背景, 总结了本区的石炭系地层特征, 认为石炭系地层具以下特点: (1)研究区位于醴陵—攸县断陷盆地的北部边缘地带, 沉积了樟树湾组这套高成熟度石英砂岩; (2)本区石炭系总体经历了多次海退-海进的循环沉积过程, 反映由陆架建设到碳酸盐台地的形成过程; (3)本区石炭系地层受地形条件控制及同生断裂的影响, 其沉积差异明显。本研究对醴陵地区石炭系石英砂岩矿的开发具指导意义。 相似文献
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