转铁蛋白的制备方法及其应用前景

转铁蛋白是一种铁结合性糖蛋白,具有多种生物学功能.对转铁蛋白的结构、功能、制备方法及应用前景进行了综述,指出了转铁蛋白分离纯化的重要性.     

光谱法研究黄腐酸与转铁蛋白的结合

正人血清转铁蛋白(Tf)在抗癌药物向主要的增生性癌细胞递送中显示出了过度表达转铁蛋白受体的潜能。黄腐酸因具有广泛的生物和药理活性而引起人们的普遍关注。黄腐酸与Tf的相互作用对深入了解黄腐酸的抗癌活性具有重要意义。本研究在生理条件下,利用荧光猝灭、热力学、同步荧光和圆二色谱(CD)法研究了黄腐酸与Tf的相互作用机制。黄腐酸与Tf结合,形成了新的复合物,并计算得出在288、298、310 K时,荧光猝灭表观缔合常数     

Vero细胞无血清培养基的优化

目的通过试验设计(design of experiments,DOE)方法和统计学分析快速优化Vero细胞无血清培养基。方法以DMEM/F12为基础培养基,通过Plackett-Burman试验、最陡爬坡试验和Box-Behnken试验考察7种添加物胰岛素、人转铁蛋白、透明质酸、牛血清白蛋白、亚硒酸钠、表皮生长因子和高密度脂蛋白对Vero细胞生长的影响,以CCK-8测定的吸光度值(A490)为响应值,优化Vero细胞无血清培养基。用最优化的因子浓度配制的Vero细胞无血清培养基培养Vero细胞,对优化结果进行验证。结果通过Plackett-Burman试验筛选出胰岛素、牛血清白蛋白和人转铁蛋白对Vero细胞生长影响较大;采用最陡爬坡试验和Box-Behnken试验进一步优化,Design-Expert 8.06软件进行回归分析,得到胰岛素、人转铁蛋白和牛血清白蛋白的最佳浓度分别为5.625μg/ml、14.034μg/ml和3.92 mg/ml,在此优化条件下的A490值为2.3,较基础培养基提高了3.41倍。用最优的胰岛素、人转铁蛋白和牛血清白蛋白浓度配制的Vero细胞无血清培养基培养Vero细胞的A490值为2.148,为预测值的93.4%,符合度较高。结论应用DOE方法快速高效地优化了Vero细胞无血清培养基,为无血清培养基的研制奠定了基础。     

利用微生物“提炼金属”

1905年西德一家工厂的大量自来水管被阻塞,拆修时发现管内沉积了许多铁末。在显微镜下观察时,从铁末中找到一种铁细菌,它能分解铁化合物,使它分解而吃进,以致死亡而使铁末沉积在管内。时隔不久,美国发现一种硫细菌,它既能分解硫化合物,又能分解铜化合物。铁细菌和硫细菌的发现,引起了许多国家     

黄鳝血清转铁蛋白的提取及表征

对从黄鳝血液中提取的蛋白层析纯化后进行生物质谱测试,确定为血清转铁蛋白. 利用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、原子力显微镜、圆二色谱法对蛋白的分子量、表面形貌、二级结构进行了表征. 结果表明,该转铁蛋白分子量为74 kDa,含量为0.750 mg/mL,含a-螺旋29.8%,b-折叠6.6%.     

电镀废盐酸处理方法研究

在电镀企业中,大部分工艺加工过程中使用盐酸来清洗加工元件的表面的铁锈,导致废盐酸的产生。这些电镀废酸的妥善处理是人们一直以来所关心的问题。通过对酸铁比的调节及计算,以及铁含量的调节及计算,并通过系列的过程控制及品质调节,最终用废盐酸制备出了比重、铁含量以及盐基度等各方面符合国家标准的水处理剂产品。     

人血浆转铁蛋白的分离与纯制

介绍了用硫酸铵盐析和 DEAE-Sephadex A-50层析技术由 Cohn 氏组分Ⅳ制备纯人血浆转铁蛋白的过程。聚丙烯酰胺凝胶电泳、免疫电泳、吸收光谱和铁结合活性等检定的结果与文献报道的一致。     

零价铁降解地下水卤代烃技术研究进展

随着卤代烃类有机污染物越来越多地出现在自然水体中,卤代烃降解工艺的研究也越来越受到人们的重视。该文简述了卤代烃的物理性质以及用途,与零价铁有关的处理卤代烃的相关工艺如零价铁还原、纳米零价铁技术、零价铁-氧化剂联用技术、零价铁-厌氧微生物技术等,展望了零价铁技术的发展前景。     

一种补血颗粒的临床疗效及安全性研究

目的:研究一种补血颗粒的临床疗效及安全性.方法:采用双盲法设计组间和自身两种对照试验,将受试者随机分为试验组(服用补血颗粒)和对照组(服用安慰剂),进行缺铁性贫血治疗试验.结果:试验组血红蛋白平均升高,血清铁蛋白、血清运铁蛋白饱和度显著增加,临床症状积分显著下降;红细胞内游离原卟啉下降差异有非常显著性;临床观察总有效率...     

纳米铁修饰SBA-16分子筛的制备及其催化性能研究

在原位合成的过程中将铁原子掺杂在分子筛的孔道中,然后利用氢气还原将骨架中的铁直接还原成金属铁,随后利用分子筛本身孔道的限域效应将单质铁原子的大小限制在纳米级。通过XRD、HRTEM和BET表征分析发现分子筛仍然保持了良好的结构,利用XPS分析了铁原子在分子筛中存在的状态,发现铁原子是以单质形式存在于分子筛的孔道中,通过HRTEM可以发现,纳米铁的颗粒大小约为5 nm,最后将其应用于苯的羟基化试验评价中,其中苯的转化率可达36%,苯酚的选择性可达89%,表现出了优异的催化性能。     

X-ray Characterization of Conformational Changes of Human Apo- and Holo-Transferrin

Human serum transferrin (Tf) is a bilobed glycoprotein whose function is to transport iron through receptor-mediated endocytosis. The mechanism for iron release is pH-dependent and involves conformational changes in the protein, thus making it an attractive system for possible biomedical applications. In this contribution, two powerful X-ray techniques, namely Macromolecular X-ray Crystallography (MX) and Small Angle X-ray Scattering (SAXS), were used to study the conformational changes of iron-free (apo) and iron-loaded (holo) transferrin in crystal and solution states, respectively, at three different pH values of physiological relevance. A crystallographic model of glycosylated apo-Tf was obtained at 3.0 Å resolution, which did not resolve further despite many efforts to improve crystal quality. In the solution, apo-Tf remained mostly globular in all the pH conditions tested; however, the co-existence of closed, partially open, and open conformations was observed for holo-Tf, which showed a more elongated and flexible shape overall.     

Molecular diagnostic and pathogenesis of hereditary hemochromatosis

Hereditary hemochromatosis (HH) is an autosomal recessive disorder characterized by enhanced intestinal absorption of dietary iron. Without therapeutic intervention, iron overload leads to multiple organ damage such as liver cirrhosis, cardiomyopathy, diabetes, arthritis, hypogonadism and skin pigmentation. Most HH patients carry HFE mutant genotypes: homozygosity for p.Cys282Tyr or p.Cys282Tyr/p.His63Asp compound heterozygosity. In addition to HFE gene, mutations in the genes that encode hemojuvelin (HJV), hepcidin (HAMP), transferrin receptor 2 (TFR2) and ferroportin (SLC40A1) have been associated with regulation of iron homeostasis and development of HH. The aim of this review was to identify the main gene mutations involved in the pathogenesis of type 1, 2, 3 and 4 HH and their genetic testing indication. HFE testing for the two main mutations (p.Cys282Tyr and p.His63Asp) should be performed in all patients with primary iron overload and unexplained increased transferrin saturation and/or serum ferritin values. The evaluation of the HJV p.Gly320Val mutation must be the molecular test of choice in suspected patients with juvenile hemochromatosis with less than 30 years and cardiac or endocrine manifestations. In conclusion, HH is an example that genetic testing can, in addition to performing the differential diagnostic with secondary iron overload, lead to more adequate and faster treatment.     

Effects of vegetable proteins on iron and zinc absorption and availability in humans

This review discusses research on the effects of vegetable protein diets on iron and zinc absorption and availability. Constituents of vegetables can have either a positive or negative effect on iron absorption. Although the use of soy protein to extend beef patties was found to decrease nonheme iron absorption in some studies, the use of soy-extended beef on a regular basis was not found to deleteriously affect the iron status (serum ferritin levels) of adult men, menstruating females or school age subjects. Factors such as phytic acid level, dietary fiber content or protein source of vegetable protein diets have been implicated in decreasing the utilization of iron and zinc by humans. The effect of the molar ratio of phytate on the zinc of the diet is controversial: some studies find a decrease in zinc absorption with an increase in the phytate to zinc molar ratio; other studies find zinc absorption more dependent on the total amount of zinc in the meal than on the presence of phytic acid. Since many people meet their energy and protein requirements from vegetable sources, attention should be given to the mineral availability of these diets.     

Irreversible changes in protein conformation due to interaction with superparamagnetic iron oxide nanoparticles

The understanding of the interactions between nanomaterials and proteins is of extreme importance in medicine. In a biological fluid, proteins can adsorb and associate with nanoparticles, which can have significant impact on the biological behavior of the proteins and the nanoparticles. We report here on the interactions of iron saturated human transferrin protein with both bare and polyvinyl alcohol coated superparamagnetic iron oxide nanoparticles (SPIONs). The exposure of human transferrin to SPIONs results in the release of iron, which changes the main function of the protein, which is the transport of iron among cells. After removal of the magnetic nanoparticles, the original protein conformation is not recovered, indicating irreversible changes in transferrin conformation: from a compact to an open structure.     

A mass spectrometric and molecular modelling study of cisplatin binding to transferrin

A combination of mass spectrometry, UV/Vis spectroscopy and molecular modelling techniques have been used to characterise the interaction of cisplatin with human serum transferrin (Tf). Mass spectrometry indicates that cisplatin binds to the hydroxy functional group of threonine 457, which is located in the iron(III)-binding site on the C-terminal lobe of the protein. UV/Vis spectroscopy confirms the stoichiometry of binding and shows that cisplatin and iron(III) binding are competitive. The binding of cisplatin has been modelled by using molecular dynamic simulations and the results suggest that cisplatin can occupy part of both the iron(III)- and carbonate-binding sites in the C-terminal lobe of the protein. Combined, the studies suggest that cisplatin binding sterically restricts iron(III) binding to the C-terminal lobe binding site, whereas the N-terminal lobe binding site appears to be unaffected by the cisplatin interaction, possibly allowing the iron(III)-induced conformational change necessary for binding to a Tf receptor.     

Human Serum Transferrin Fibrils: Nanomineralisation in Bacteria and Destruction of Red Blood Cells

Fibrils formed by human serum transferrin [(1–3 μM ) apo‐Tf, partially iron‐saturated (Fe_0.6‐Tf) and holo‐Tf (Fe₂‐Tf) forms], from dilute bicarbonate solutions, were deposited on formvar surfaces and studied by electron microscopy. We observed that possible bacterial contamination appears to give rise to long, pea‐pod‐like (PPL) structures for Fe₂‐Tf, attributable to the formation of polyhydroxybutyrate (PHB) storage granules, under the nutrient‐limiting conditions used. These PPL structures contained periodic nanomineralisation sites susceptible to uranyl stain. Extended incubation of transferrin solutions (about four days) gave rise to extensive transferrin fibril structures. Optical microscopy and AFM studies showed that red blood cells (RBCs) readily adhere to these fibrils. Moreover, the fibrils appear to penetrate RBC membranes and to induce rapid cell destruction (within about 5 h). It is speculated that in situations in vivo where transferrin fibrils can form, such interactions might have adverse physiological consequences, and further studies could aid the understanding of related pathological events.     

Transferrin: from inorganic biochemistry to medicine

Transferrin is one of the key proteins of iron metabolism in mammalians. It is responsible for the transfer of the essential iron(III) ions through the biological fluids from absorption to storage and utilization sites. Moreover, transferrin is involved in the metabolism of other metal ions that are either trace or toxic elements. In recent years the crystal structure of transferrin has been solved at high resolution. This has allowed an extensive reinterpretation of the many spectroscopic studies carried out on this protein in the last decade as well as the elucidation of some interesting structure-function relationships. We review here recent progresses in transferrin biochemistry, particular focus being given to those aspects that are relevant from a medical point of view.     

A Possible Way to Relate the Effects of SARS-CoV-2-Induced Changes in Transferrin to Severe COVID-19-Associated Diseases

SARS-CoV-2 infections are responsible for the COVID-19 pandemic. Transferrin has been found to explain the link between diseases associated with impaired iron transport and COVID-19 infection. The effect of SARS-CoV-2 on human whole blood was studied by differential scanning calorimetry. The analysis of the thermal transition curves showed that the melting temperature of the transferrin-related peak decreased in the presence of SARS-CoV-2. The ratio of the under-curve area of the two main peaks was greatly affected, while the total enthalpy of the heat denaturation remained nearly unchanged in the presence of the virus. These results indicate that SARS-CoV-2, through binding to transferrin, may influence its Fe³⁺ uptake by inducing thermodynamic changes. Therefore, transferrin may remain in an iron-free apo-conformational state, which depends on the SARS-CoV-2 concentration. SARS-CoV-2 can induce disturbance in erythropoiesis due to toxicity generated by free iron overload.