共查询到19条相似文献,搜索用时 93 毫秒
1.
2.
3.
熔盐合成法制备CaTiO3粉体的研究 总被引:2,自引:0,他引:2
以TiO2及CaCO3为原料,CaCl2为反应介质,对熔盐合成法制备CaTiO3粉体进行研究,并与固相合成法进行比较.结果表明,熔盐合成法可将纯相CaTiO3的合成温度从固相合成法所需的1 400 ℃降至800 ℃,熔盐法合成的CaTiO3粉末粒度较小(<0.5 μm),分布均匀,且具有很高的分散性.在熔盐合成法中由于CaCO3及TiO2在熔融CaCl2中有较高的溶解度,两者可在其中通过"溶解析出"机理进行反应,从而在较低的温度下生成单一相的CaTiO3. 相似文献
4.
用固相合成法成功地合成了生长激素释放肽 GHRP,其氨基酸组成和相对分子质量测定值均符合理论值。实验表明 GHRP对幼龄小鼠的生长有明显的促进作用 ,并对合适的注射剂量范围 ,给药年龄和给药方式进行了研究 相似文献
5.
4种含RGD的短肽对细胞粘附作用的影响 总被引:1,自引:0,他引:1
从两方面对比研究了4种含Arg-Gly-Asp(RGD)的细胞粘附肽RGD,RGDS,RGD-(NH2)2即RGE-NH2和RGDS-NH2对细胞粘附的影响. 一方面研究了固定在聚乙交酯丙交酯共聚物(PLGA)膜上的4种细胞粘附肽通过其细胞定向作用对大肠癌细胞(HCT-8)和人成骨肉瘤细胞(OS732)细胞粘附性
的促进作用; 另一方面研究了外源性细胞粘附肽对HCT-8和OS732在纤维连接蛋白(FN)上粘附的竞争性抑制作用. 结果发现,除了RGD-(NH2)2,其他3种肽都具有明显抑制细胞粘附的作用且具有一定的浓度依赖关系,其中以RGDS和RGDS-NH2的能力最强,RGD稍弱. 对于HCT-8细胞,3种肽的最大抑制率分别为53.3%,
56.3%,37.5%;而对OS732细胞,3种肽的最大抑制率分别为50.9%,49.8%,34%. 相似文献
6.
利用Fmoc固相合成法合成了一种基质金属蛋白酶—间质胶原酶(MMP-1)活性中心的肽片段,通过RP-HPLC对粗肽进行纯化得到了高纯度的多肽,经电喷雾质谱、^1HNMR进行了表征.实验结果表明,Fmoc法合成粗肽的产率为76.0%,纯度为86.5%,经RP-HPLC纯化后纯度达到99.1%. 相似文献
7.
以阿昔洛韦和琥珀酸酐为原料,100 mL DMF为反应媒介,加入0.7 mL三乙胺,合成琥珀酰阿昔洛韦[9-(2-丁二酸单酰乙氧基甲基)鸟嘌呤](SACV),然后利用Fmoc固相合成法合成三个新的阿昔洛韦二肽衍生物(SACV-Glu-Lys,SACV-Glu-Ala,SACV-Val-Lys).利用1H NMR和ESI-MS分析手段对其结构进行表征.并考察了二肽修饰过的阿昔洛韦,水溶性,油脂分配系数.结果表明含有较长的侧链酸性氨基酸与碱性氨基酸形成的二肽所修饰阿昔洛韦,既可以较大的提高阿昔洛韦(ACV)的水溶性又能够得到油水分配系数较高的ACV二肽衍生物. 相似文献
8.
9.
RGD三肽的合成与生物活性检测 总被引:2,自引:0,他引:2
在生物材料表面上先接枝RGD,然后再在其上种植和培养内皮细胞,这是目前改善心血管材料血液相容性最好的方法之一。采用液相合成法合成了RGD 三肽并对其进行了生物活性检测,证实用液相合成的 RGD 短肽具有促进材料与内皮细胞粘附的生物活性。 相似文献
10.
高脂血症是引起心脑血管疾病的主要原因之一。Ser-Asp-Glu 三肽(SDE)在对血浆中低密度脂蛋白(LDL)的识别及特异性吸附起关键性作用。本实验采用 DCC/HOBt 液相法,合成三肽(SDE)。重点研究反应温度、反应时间和原料配比对 SDE 产率的影响。结果表明本实验成功合成出SDE 三肽。 相似文献
11.
12.
13.
14.
15.
16.
Biomimetic synthesis and optimization of cyclic peptide antibiotics 总被引:11,自引:0,他引:11
Molecules in nature are often brought to a bioactive conformation by ring formation (macrocyclization). A recurrent theme in the enzymatic synthesis of macrocyclic compounds by non-ribosomal and polyketide synthetases is the tethering of activated linear intermediates through thioester linkages to carrier proteins, in a natural analogy to solid-phase synthesis. A terminal thioesterase domain of the synthetase catalyses release from the tether and cyclization. Here we show that an isolated thioesterase can catalyse the cyclization of linear peptides immobilized on a solid-phase support modified with a biomimetic linker, offering the possibility of merging natural-product biosynthesis with combinatorial solid-phase chemistry. Starting from the cyclic decapeptide antibiotic tyrocidine A, this chemoenzymatic approach allows us to diversify the linear peptide both to probe the enzymology of the macrocyclizing enzyme, TycC thioesterase, and to create a library of cyclic peptide antibiotic products. We have used this method to reveal natural-product analogues of potential therapeutic utility; these compounds have an increased preference for bacterial over eukaryotic membranes and an improved spectrum of activity against some common bacterial pathogens. 相似文献
17.
Biochemistry and molecular cell biology of diabetic complications 总被引:255,自引:0,他引:255
Brownlee M 《Nature》2001,414(6865):813-820
Diabetes-specific microvascular disease is a leading cause of blindness, renal failure and nerve damage, and diabetes-accelerated atherosclerosis leads to increased risk of myocardial infarction, stroke and limb amputation. Four main molecular mechanisms have been implicated in glucose-mediated vascular damage. All seem to reflect a single hyperglycaemia-induced process of overproduction of superoxide by the mitochondrial electron-transport chain. This integrating paradigm provides a new conceptual framework for future research and drug discovery. 相似文献
18.
Screening of functionalized self-assembling peptide nanofiber scaffolds with
angiogenic activity for endothelial cell growth 总被引:1,自引:0,他引:1
Promotion of angiogenesis in tissue engineering is of vital significance to the survival of transplants,which leads the way of tissue regeneration.In this study,we screened six short peptides with potentially angiogenic activities to functionalize self-assembling peptide nanofiber scaffolds RADA16-I(Ac-(RADA)_4-CONH_2).Fluorescence microscopy images of endothelial cells morphology on peptide scaffolds exhibited good cell attachments and Survivals on these six functionalized peptide scaffolds, especially ... 相似文献
19.
A unifying hypothesis of cell adhesion 总被引:5,自引:0,他引:5