Conventionally, most of the substitution of amino acids in important protein positions is expected to eliminate the function. However, in some soluble globular proteins, we identify non-conservation positions that various substitutions produce progressive functional changes; We consider “Rheostats” of this evolution. Here, we report a strong rheostat position in integral membrane protein, NA + / Taurocholate Cotransporting Polypeptide (NTCP), at the location of the polymorphism that is pharmacologically relevant (S267F). Functional studies are carried out for all 20 substitutions (“S267x”) with three substrates (taurocholate, estrone-3-sulfate and rosuvastatin).
The S267X set shows a strong reosatic effect on overall transportation, and individual replacement shows the effects vary in transportation kinetics (KM and Vmax) and substrate specificity. To assess protein stability, we measure surface expression and use the Rosetta software suite to model the structure and change of S267X stability. Despite being buried near the substrate binding site, the S267X substitution is easily accommodated in the NTCP structure model. In various changes, calculated stability correlates with differences in surface expression, but no parameters correlated with changed transport. Thus, the substitution in the position of Rheostat 267 has a broad effect on the phenotype of this integral membrane protein. We then propose that the polymorphic position in other proteins might be the location of the position of Rheostat.
The study mechanism of abnormal accumulation and deposition of amyloid islet polypeptides with cold ionization mass spectrometry
Abnormal accumulation and deposition of polypeptide pullet amyloid (IAPP) is an important cause of type-2 type diabetes mellitus (T2DM). General anti-amyloid strategies employ inhibitors to prevent the formation of oligomers and cytotoxicity caused by them, thereby reducing the production of amyloid fibers. Therefore, the real characterization of the Oligomers formed at the initial stage of aggregation is very important to understand the IAPP structure and the development of T2DM drugs.
For the first time, in this study, the original Ionization Spectrometry Technology of the original spray (CSI-MS) was hired to characterize the oligomers. It was found that CSI was more suitable for determining this unstable species compared to traditional MS ESI. Ion strength, organic solvents and pH all have an effect on the characterization of oligomers and stability of protein conformation. MS / MS experiment shows that odd charging dimer ions consist mainly of two monomer products. In addition, the CSI-MS method for quick screening of IAPP-inhibitors was established and two most potential inhibitors (routine and quercitrin) were played from a series of flavonoids.
Then, the relationship between activities and mechanisms between flavonoids and IAPP is studied. The results showed that the 3-oh chain and sugar played a vital role and hydrogen bonds was the power of the main binding. We subsequently confirm that routine and quercitrin can effectively inhibit the formation of IAPP fibers by fluorescence and TEM experiments. This study provides new insights to analyze the IAPP structure and potential drug screening for T2DM.
Evaluation of chromatographic parameters in the chromatography of the amino acid supercritic liquid as a polar analyte model and expanded to the separation of polypeptides
Chromatographic parameters have been evaluated regarding amino acid acid supercritical chromatography as a model compound for polar substances and is subject to biochemical and biopharmaceutical interests. The inherent hydrofilisity requires the appropriate chromatographic conditions regarding the stationary phase and moves to obtain suitable solubility and peak performance. Ten different stationary phases in polarity and types of ligands including neutral and charged with investigated regarding selectivity, peak performance, and complementary orthogonality. Mobile phase compositions regarding solvents and types of buffer additives by varying hydrophobicity degrees of acid and base and substitution level in the case of basic amines. The addition of water to methanol solvents is then found is very important to get high peak performance. Some complementary selectivity can be obtained depending on the choice of column.
A clinically-relevant polymorphism in the Na +/taurocholate cotransporting polypeptide (NTCP) occurs at a rheostat position
Variations of temperature and pressure are basically only influenced by retention without selectivity change. The appropriate conditions obtained for amino acids are then successfully applied to oligo and polypeptides allow the separation of 4 polypeptides and differ in just one of 39 amino acids, thus mimicing analysis of biotransformation reaction products. Utilization of water as a cellphone additive and sulfonate acid as a buffer agent can function as a generic methodology for polar compounds and charged like amino containing biomolecules.
Polypeptide nanoparticles with pegylated ph-sheddable for enhanced drug delivery
Microenvironment tumor variations provide tools for the construction of nanomedicina responsive stimulus to increase the efficacy of drug administration. Here, the assembly of polypeptide nanoparticles loaded by drugs (NPS) with modification of PH-Sheddable Poly (Ethylene Glycol) (PEG) is prepared to improve therapeutic efficiency. Poly (L-Lysine) and Poly (L-Glutamic Acid) are assembled themselves to make Polypeptide NPS with electrostatic interactions, followed by a firewell based on a syrading reaction. The size of the NP can be controlled by setting the molecular weight or polypeptide ratio.
Description: A competitive ELISA for quantitative measurement of Rat Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Rat Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Rat Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Porcine Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Porcine Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Porcine Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Canine Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Canine Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Canine Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Goat Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Goat Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Goat Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Mouse Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Mouse Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Mouse Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Human Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Human Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
Description: A competitive ELISA for quantitative measurement of Human Islet amyloid polypeptide in samples from blood, plasma, serum, cell culture supernatant and other biological fluids. This is a high quality ELISA kit developped for optimal performance with samples from the particular species.
PEG coating can be issued on tumor acid environments to reverse surface load and reduce NP size, which effectively increases cell absorption. In addition, the existence of reducing reagents (eg, glutathione) in cancer cells induces drugs (i.e., cisplatin) releases from polypeptide NPS and then produces cell toxicity. This reported method highlights the technique of transformed polypeptide drug operators, which provides promising ways to increase the efficacy of drug administration.
