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Elastic Behaviors of Adsorbed Protein-like Chains
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作者 孙婷婷 马海珠 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第1期11-17,I0001,共8页
Elastic behaviors of protein-like chains are investigated by Pruned-Enriched-Rosenbluth method and modified orientation-dependent monomer-monomer interactions model. The protein-like chain is pulled away from the attr... Elastic behaviors of protein-like chains are investigated by Pruned-Enriched-Rosenbluth method and modified orientation-dependent monomer-monomer interactions model. The protein-like chain is pulled away from the attractive surface slowly with elastic force acting on it. Strong adsorption interaction and no adsorption interaction are both considered. We calculate the characteristic ratio and shape factor of protein-like chains in the process of elongation. The conformation change of the protein-like chain is well depicted. The shape of chain changes from “rod” to “sphere” at the beginning of elongation. Then, the shape changes from “sphere” to “rod”. In the end, the shape becomes a “sphere” as the chain leaves away from the surface. In the meantime, we discuss average Helmoholtz free energy per bond, average energy per bond, average adsorbed energy per bond, average α-helical energy per bond, average β-sheet energy per bond and average contact energy per bond. On the other hand, elastic force is also studied. It is found that elastic force has a long plateau during the tensile elongation when there exists adsorption interaction. This result is consistent with SMFS experiment of general polymers. Energy contribution to elastic force and contact energy contribution to elastic force are both discussed. These investigations can provide some insights into the elastic behaviors of adsorbed protein chains. 展开更多
关键词 Elastic behavior Adsorbed protein-like chain Pruned-Enriched-Rosenbluth method Orientation-dependent monomer-monomer interactions model
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离子交换/8-羟基喹啉荧光法分别测定天然水中的无机和有机单核铝 被引量:13
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作者 干宁 毕树平 +1 位作者 邹公伟 魏宗波 《分析化学》 SCIE EI CAS CSCD 北大核心 2000年第11期1375-1379,共5页
采用离子交换 氯仿萃取 8 羟基喹啉荧光法 ( 8 Ox CF EF)分别测定了天然水样中的无机和有机单核铝 ,与Driscoll建立的铝形态区分法进行了比较 ,结果一致。本法优点是 :可以直接测定水中的无机单核铝 ,减少了实验误差。
关键词 无机单核铝 有机单核铝 荧光光度法 天然水 测定
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花序花期喷水对“西拉”葡萄果实品质的影响
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作者 刘迪迪 谢沙 +1 位作者 王珍 张振文 《北方园艺》 CAS 北大核心 2017年第12期26-30,共5页
"西拉"葡萄(Vitis vinifera L.)果穗紧密,果粒挤压变形严重,内部果粒着色差,果实成熟期病害严重,品质难以保证。葡萄开花期连续降雨可导致坐果降低,通过试验模拟葡萄开花期降雨,可以一定程度上降低葡萄坐果率,达到疏松果穗的... "西拉"葡萄(Vitis vinifera L.)果穗紧密,果粒挤压变形严重,内部果粒着色差,果实成熟期病害严重,品质难以保证。葡萄开花期连续降雨可导致坐果降低,通过试验模拟葡萄开花期降雨,可以一定程度上降低葡萄坐果率,达到疏松果穗的目的。试验以"西拉"葡萄为试材,设置葡萄开花前期、后期和整个花期3个喷水处理,每天喷一次水,在葡萄果实膨大期调查坐果率;葡萄成熟后调查葡萄发病率,测定葡萄还原糖、总酸、总酚、总单宁、总花色苷、单体花色苷、单体酚类含量。结果表明:花期喷水能提高葡萄浆果品质,且受喷水次数与时期影响较大。整个花期每天喷一次水,"西拉"葡萄品质表现最佳,开花后期喷水比前期喷水的葡萄浆果品质更好。因此,建议在葡萄管理中,若开花期天气连续晴朗,可以通过花序喷水疏松葡萄果穗,提升葡萄品质。 展开更多
关键词 “西拉”葡萄 花序喷水 单体花色苷 单体酚类
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一种新的B链C端去四肽胰岛素的研制方法 被引量:1
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作者 王一成 石嘉豪 +1 位作者 张元兴 费俭 《细胞生物学杂志》 CSCD 2007年第5期771-776,共6页
报道了将单体胰岛素前体(MIP)经胰蛋白酶和羧肽酶B两步连续酶切获得B链C端去四肽胰岛素(DTI)的方法。MIP由甲醇酵母表达,最高发酵表达量达到150mg/L。发酵液中MIP通过疏水层析,分子筛初步纯化后直接进行酶切,在胰蛋白酶酶切3h后加入抑制... 报道了将单体胰岛素前体(MIP)经胰蛋白酶和羧肽酶B两步连续酶切获得B链C端去四肽胰岛素(DTI)的方法。MIP由甲醇酵母表达,最高发酵表达量达到150mg/L。发酵液中MIP通过疏水层析,分子筛初步纯化后直接进行酶切,在胰蛋白酶酶切3h后加入抑制剂paminobenzamidine处理15min,然后直接加入羧肽酶B酶切6h,再通过反相柱纯化即可得到纯品DTI,从分子筛到最后DTI,总纯化得率达到77%。按中国药典小白鼠惊厥法测定得DTI的生物活力为22IU/mg,是胰岛素的80%,在Superdex G-75分子筛上测定DTI的解离聚合曲线,证明其是单体。 展开更多
关键词 单体胰岛素前体 B链C端去四肽胰岛素 胰蛋白酶 羧肽酶B
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