182 results about "Isoelectric point" patented technology

The invention relates generally to compositions and methods for purifying the desired species from a mixture of desired heterodimer and contaminating homodimer immunoglobulin variants by modifying the isoelectric point(s) of the individual chains.

The invention relates generally to compositions and methods for purifying the desired species from a mixture of desired heterodimer and contaminating homodimer immunoglobulin variants by modifying the isoelectric point(s) of the individual chains.

The invention discloses synthesized XVII type humanized collagen as well as a preparation method and application thereof, and particularly relates to the technical field of genetic engineering. The amino acid sequence of the recombinant XVII type collagen is as shown in SEQ ID NO. 1. According to the invention, key functional domains (five high-hydrophilicity and high-stability peptide fragments such as 641-685 and the like) in a human XVII type collagen alpha1 chain are retained, and non-functional regions are removed. The 100% human source sequence coverage rate is adopted, the immunogenicity risk of animal source collagen is completely avoided, and the biocompatibility is excellent. The functional peptide fragment is repeated twice to form a stable structure of 210 amino acids, so that the functional activity of the protein is enhanced. The theoretical isoelectric point (pI = 6.07) is close to the pH value (7.4) of human tissue fluid, the dissolvability is excellent, and the applicability is high.

The invention provides peony polypeptide for reducing uric acid as well as a preparation method and application thereof, and belongs to the technical field of biology. The preparation method comprises the following steps: soaking and cleaning peony seed meal with ethanol, centrifuging at 3000-500r for 30-50min, taking a first precipitate, drying the first precipitate, adding water, adjusting the pH value to 9-10, carrying out alkali extraction at 45-55 DEG C for 70-80min, taking supernate, adjusting the pH value to an isoelectric point, and taking a second precipitate; the second precipitate is subjected to enzymolysis for 2-8 h under the conditions that the temperature is 20-80 DEG C, the pH is 5-9, and the protease addition amount is 1500-9000 U / g, and the peony polypeptide capable of reducing uric acid is obtained. The compound has inhibitory activity on xanthine oxidase, and the active components of the compound have stability and functionality by adopting ultrafiltration grading and simulated digestion model exploration.

The invention discloses recombinant humanized XVII type and recombinant humanized I type collagen sequences as well as a synthesis method and application thereof, the recombinant humanized collagen comprises one or more functional sequences in cell integrin binding sites such as R / KGD, GER / K, GVMGFP and DGEA, the molecular weight is 6-14 kDa, and the recombinant humanized collagen simultaneously surrounds an isoelectric point, has hydrophilicity and hydrophobicity, and can be used for preparing the recombinant humanized collagen. Reasonable design is carried out on information such as an antigen epitope, GXY sequence stability, protease degradation sites and the like, so that the recombinant humanized collagen has relatively good stability and also has biological activity of promoting cell proliferation and resisting wrinkles and tightening.

The invention belongs to the technical field of biomedical engineering, and particularly relates to a polypeptide preparation method for preparing a GLP-1 analogue through tandem expression. According to the method, a coding gene sequence of the GLP-1 analogue is repeatedly connected in series for a plurality of times, and then expression preparation is carried out on the basis of a genetic engineering technology. The inventor optimizes a series-connected polypeptide structure by adding a section of key peptide sequence. The key peptide serving as a leading peptide can greatly improve the expression quantity of the strain in the fermentation expression process; as a linked peptide, the key peptide sequence can effectively improve the recognition capability of enzyme digestion sites on one hand and can adjust the overall isoelectric point of the sequence on the other hand, so that the solubility, enzyme digestion yield and purity of a target product can be improved. Preliminary experiment results show that the expression quantity of the polypeptide prepared through expression is extremely high, the enzyme digestion efficiency is good, the good enzyme digestion efficiency can be achieved under the condition that the enzyme dosage is low, and the yield and purity of the final GLP-1 analogue are high.

The invention relates to the field of biological medicine preparation, and particularly provides liraglutide precursor peptide tandem recombinant fusion protein, polynucleotide, recombinant expression plasmid, engineered host cell and a method for preparing target polypeptide. The recombinant fusion protein is fusion peptide-target polypeptide-(linker peptide-target polypeptide) n from the N terminal to the C terminal, n is a positive integer from 4 to 6, the fusion peptide is SEQ ID NO.1, the target polypeptide is liraglutide precursor peptide, the linker peptide comprises a spacer peptide and a protease restriction enzyme cutting site, the spacer peptide is SEQ ID NO.2, the isoelectric point of the recombinant fusion protein is 4.6-4.7, and the average hydrophilic value is-0.780--0.765. The proportion of the target polypeptide in the recombinant fusion protein is high, use of solvents under extreme conditions is avoided in the production process, the enzyme digestion efficiency is high, and the product purity and yield are high.

The invention relates to a method for separating out and condensing specific protein in liquid for dyeing and detection. The liquids include but are not limited to human samples, human blood, saliva, urine and the like. The liquid is diluted and its pH is raised or lowered to form a mixed liquid. Placing the mixed solution in an electrostatic field, moving the specific protein in the mixed solution to one side of the mixed solution, accurately dropwise adding an acidic or alkaline solution, adjusting the pH value of the mixed solution, enabling the pH value of the mixed solution to reach the isoelectric point of the specific protein, and enabling the specific protein to be separated out and precipitated on one side of the mixed solution. In addition, according to the sequence of the pH values from large to small or from small to large, the isoelectric points of all the specific proteins can be traversed in the process, and all the specific proteins can be separated out and precipitated in the same area of the mixed solution.

The invention relates to the field of biological medicine preparation, and particularly provides canagliflozin precursor peptide tandem recombinant fusion protein, polynucleotide, recombinant expression plasmid, engineered host cell and a method for preparing target polypeptide. The recombinant fusion protein is a fusion peptide-target polypeptide-(linker peptide-target polypeptide) n from an N terminal to a C terminal, n is a positive integer of 4-6, the fusion peptide is SEQ ID NO.1 or SEQ ID NO.2, the target polypeptide is a canagliptin precursor peptide, the linker peptide comprises a spacer peptide and a protease restriction enzyme cutting site, the spacer peptide is SEQ ID NO.3, the isoelectric point of the recombinant fusion protein is 5.5-6.5, and the average hydrophilic value is-0.85--0.96. The invention creatively provides a method for preparing the canagliflozin precursor peptide by using a gene recombination technology, the proportion of the target polypeptide in the recombinant fusion protein is high, the use of a solvent under extreme conditions is avoided in the production process, the enzyme digestion efficiency is high, and the product purity and yield are high.

The application discloses a vaccine and a preparation method thereof, and the preparation method comprises the following steps: mixing an acidic protein antigen solution containing a phosphate buffer solution with an aluminum adjuvant to make the molar ratio of phosphorus and aluminum below 0.9, so as to obtain an acidic protein vaccine; or mixing the aluminum adjuvant with a solution containing phosphate ions to make the molar ratio of phosphorus and aluminum above 0.2, and then mixing the aluminum adjuvant with an alkaline protein antigen solution containing a phosphate buffer solution, so as to obtain an alkaline protein vaccine; wherein the acidic protein antigen is any kind of protein antigen with a net negative charge; and the alkaline protein antigen is any kind of protein antigen with a net positive charge. According to the preparation method, the molar ratio of phosphorus and aluminum is adjusted to a specific range according to the net charge of the protein antigen, so that the isoelectric point of the aluminum adjuvant can be effectively changed, the charge carried by the aluminum adjuvant is opposite to the charge carried by the protein antigen, and then the aluminum adjuvant and the protein antigen are attracted to each other through electrostatic interaction. The vaccine antigen prepared by the method has high antigen adsorption rate and good stability, the preparation method is simple, and the method is suitable for industrial application.

The application discloses a biosynthesis method of blue copper peptide, comprising the following steps: synthesizing a recombinant protein according to an amino acid sequence shown in SEQ ID NO. 1, synthesizing a gene coding the recombinant protein, constructing a recombinant plasmid by using the gene, transferring the recombinant plasmid into a host bacterium, carrying out fermentation culture to induce protein expression, separating the protein, carrying out enzyme cutting and purification, and finally carrying out complexing with copper ions to obtain the blue copper peptide. Compared with the prior art, the biosynthesis method of the blue copper peptide has the advantages of low production cost, green environmental protection and high yield by optimizing the design of the fusion protein, and the yield of the final product can be significantly improved, and the fusion protein has better structure and isoelectric point characteristics.

The application provides a fluorine-doped Fe-N-C composite material and a preparation method and application and regeneration thereof, and belongs to the technical field of water pollution. In the application, an iron precursor, a zinc salt, an organic ligand and an organic solvent are mixed to synthesize Fe-doped metal organic framework Fe@ZIF-8 material, and then the Fe@ZIF-8 material is carbonized into Fe-N-C material; then the Fe-N-C material is mixed with a fluorine source and subjected to secondary carbonization to obtain the fluorine-doped Fe-N-C composite material. In the application, fluorine atoms are introduced into the Fe-N-C material to produce axial coordination with Fe of the FeN4 center, the fluorine element with high electronegativity can effectively improve the isoelectric point of the Fe-N-C material, the reaction activity of the material is enhanced, the Fe leaching of the material in the reaction process is inhibited, and the stability of the material is improved. In addition, the prepared fluorine-doped Fe-N-C composite material can be reused through fluorine-doping regeneration, and high reduction activity and stability can be maintained.

The present application relates to the technical field of biological medicine, and particularly relates to a method for extracting and determining selenoprotein from selenium-rich lycoperdon pygmaeum mycelium, wherein the lycoperdon pygmaeum mycelium fermented by a 20L biological culture tank is dried in a vacuum drying box, ground into standard powder through a 100-mesh sieve, 0.5g of the standard powder is weighed, a 0.05mol / L NaOH solution is added, ultrasonic-assisted extraction is performed, then centrifugation is performed at a speed of 3000r / min for 15min, the supernatant is adjusted to an isoelectric point, centrifugation is performed again to obtain a protein precipitate, and finally the protein precipitate is dried in a freeze dryer to obtain a protein sample. The present application is dedicated to using the selenium-rich lycoperdon pygmaeum mycelium as raw material, adopting ultrasonic extraction, optimally optimizing the extraction process of selenoprotein, quantitatively analyzing the selenium content in the protein, detecting the change of the type and quantity of amino acids before and after selenium enrichment through a thin layer chromatography test, and understanding the influence of selenium on the amino acids in the lycoperdon pygmaeum mycelium.

A method comprising introducing, at a first time, a sample containing a plurality of analytes and a plurality of isoelectric point (pI) markers in a conductive medium into a capillary, each pI marker from the plurality of pI markers having a known isoelectric point from a plurality of isoelectric points, the plurality of pI markers including a subset of pI markers, each pI marker from the subset of pI markers being configured to be excited by light of a wavelength within a known excitation range of wavelengths to emit a non-native fluorescence signal at a wavelength within a range of emission wavelengths; separating, at a second time after the first time, the plurality of pI markers and at least a subset of the plurality of analytes, each pI marker and each analyte being focused according to their isoelectric points, by applying a voltage across the capillary; eluting a portion of the sample that includes at least one of an analyte from the plurality of analytes or a pI marker from the subset of pI markers into a well at a third time after the second time; probing the portion of the sample including the at least one of the analyte or the pI marker from the subset of pI markers with light within the known excitation range of wavelengths to cause the pI marker to emit the non-native fluorescence signal; and detecting the non-native fluorescence signal indicating a presence of the pI marker in the portion of the sample.

The invention relates to the field of bioengineering, in particular to a construction method and application of an amylopectin ternary nano assembly with a high assembly index. The invention provides a construction method of a ternary nano assembly. The construction method comprises the following steps: S1, extracting amylopectin of bulk crops by adopting an ethanol sedimentation method; s2, extracting endogenous lipids of fruits of completely mature bulk crops by adopting a supercritical carbon dioxide extraction method; s3, extracting endogenous proteins of fruits of immature bulk crops by adopting an isoelectric precipitation method; s4, the amylopectin, the endogenous lipid and the endogenous protein are subjected to a self-assembly reaction, and the ternary nano assembly is obtained. The particle size of the ternary complex can reach nanometer, and the ternary complex is high in CI, high in SDS content, low in multi-stage digestion rate, stable in blood sugar release process and good in chewiness.

The present invention is in the field of protein compositions, in particular protein compositions for infant milk formula. The protein compositions according to the invention comprise whey protein, casein and high isoelectric point proteins, such as those having an isoelectric point of at least 6.0. The present invention further relates to the uses of the protein compositions.

Provided herein are pharmaceutical compositions and formulations of a conjugate comprising a first protein, such as an anti-VEGF antibody, conjugated to a phosphorylcholine-containing polymer, and a second protein that is not conjugated to a phosphorylcholine-containing polymer. The second protein can be the same as the first protein, or can be different. In some embodiments, the pH of the formulation is different from the isoelectric point (pI) of the second protein so as to prevent or reduce turbidity of the formulation. Also provided are methods of preparing the formulations, methods of use thereof, and kits with pre-filled syringes containing the formulations.

The invention discloses a pearl sac antibacterial peptide and application thereof, and belongs to the technical field of biological medicine. The amino acid sequence of the gene is KRLF. According to the present invention, the theoretical molecular weight is 562.76 Da, the isoelectric point is 11.54, and the net charge is + 2 when the pH value is 7.0, and the antibacterial experiment result shows that the polypeptide has broad-spectrum and efficient antibacterial activity, and has significant inhibition effect on the proliferation of Gram-positive bacteria and Gram-negative bacteria. Safety evaluation experiment results show that the antibacterial peptide is beneficial to proliferation of keratinocytes and fibroblasts and is safe and non-toxic.

The present invention provides a method of modulating a molecular mass of a fusion polypeptide, wherein the fusion polypeptide comprises a target polypeptide fused to a tag suitable for affinity purification or detection of the target polypeptide, wherein the tag comprises at least one constant domain of an immunoglobulin light chain or orthologous polypeptide or fragment thereof and wherein the molecular mass and / or an isoelectric point of the fusion polypeptide is modulated by increasing the molecular mass of the tag via combining the one constant domain of an immunoglobulin light chain or orthologous polypeptide or fragment thereof with one or more further constant domain(s) of an immunoglobulin light chain or orthologous polypeptide(s) or fragment(s) thereof; wherein the constant domain of the immunoglobulin light chain or orthologous polypeptide or fragment thereof of the tag is monomeric; and wherein optionally the target polypeptide is fused to the tag via a first linker. The invention further provides a fusion polypeptide obtained or obtainable by this method. The invention also provides a tag and a fusion polypeptide comprising the tag.

The embodiments described herein relate to free electrophoresis devices or apparatuses on a horizontal plane without other fluid dynamics forces than gravity, and apparatuses and methods for separating and precipitating an analyte of interest from a sample by sequentially adjusting the pH of the solution and focusing and separating the analyte of interest according to its respective isoelectric point. The apparatuses and methods include allowing the sample to be fluid kinetically at rest on a horizontal plane, applying an electric field parallel to the horizontal plane by an anode and a cathode on both sides of the sample, and then moving to focus and precipitate the analyte of interest fractions according to their respective isoelectric points.

The present invention provides a method for producing an inorganic particle-containing slurry, by which the number of coarse particles can be sufficiently reduced. The present invention is a method for producing an inorganic particle-containing slurry, which comprises: a step of preparing an inorganic particle dispersion containing inorganic particles and a dispersing medium, and having a pH less than the isoelectric point of the inorganic particles; and a step of adding an alkaline compound to the inorganic particle dispersion in such a manner that the pH does not reach the isoelectric point of the inorganic particles.

To provide boehmite in which a polymer dispersant is adhered or bonded to a particle surface and which does not exhibit dilatancy and is excellent in dispersibility. To provide a method for producing boehmite by adding a dispersant to a slurry of aluminum hydroxide and water and subjecting the slurry to hydrothermal treatment, by which boehmite not exhibiting dilatancy and excellent in dispersibility can efficiently be produced.SOLUTION: The present invention relates to boehmite in which a polymer dispersing agent is attached or bonded to surfaces of particles of the boehmite, the boehmite having a carbon content of 0.01% by weight to 0.17% by weight, an isoelectric point of pH2. 9 to 6.7, and exhibiting no dilatancy. The present invention relates to a method for producing the boehmite, including subjecting a slurry containing aluminum hydroxide, a polymer dispersant in an amount of 0.03% by weight to less than 1% by weight based on the weight of the aluminum hydroxide, and water to a hydrothermal treatment.SELECTED DRAWING: Figure 1

An antimicrobial peptide against Bacillus cereus, a preparation method therefor and a use thereof. The antimicrobial peptide against bacillus cereus has the general amino acid sequence formula of [KR]GG[KR]XC[FWY]C[KR]X[KR][FWY]C[LIAV]CXG[KR][KR], wherein the antimicrobial peptide XWC26 has a strong antibacterial activity against Bacillus cereus, efficiently inhibiting the spore germination of Bacillus cereus, and effectively controlling Bacillus cereus contamination in food. The antimicrobial peptide against bacillus cereus has the amino acid sequence of KGGKLCWCKNKWCICLGKR, with a molecular weight of 2224.79 Da, an isoelectric point of 9.70, and a net charge of 6. The antimicrobial peptide also has the advantages of high stability, reduced risk of drug resistance induction, high synthesis efficiency, low production costs, etc.

The invention relates to a preparation method of a conductive cellulose nanocrystal composite hydrogel type multifunctional force-electricity sensing material. The coating amount of polyaminophenylboronic acid finally polymerized on cellulose nanocrystal is regulated and controlled by controlling the feeding ratio of a cellulose nanocrystal carrier to an aminophenylboronic acid monomer as well as the feeding ratio of the aminophenylboronic acid monomer to a free radical initiator; and finally, the conductivity and the dispersity of the PAC are controlled. The PAC suspension is subjected to deprotonation regulation and control to avoid gelatin isoelectric points when being compounded with gelatin, so that the interfacial compatibility during compounding is controlled, and the mechanical property and the conductivity of the hydrogel are improved; the sol is subjected to low-temperature cooling and gelatinization to prepare a mechanical-electric dual-function integrated cellulose nanocrystal composite gelatin hydrogel material, and a multifunctional mechanical-electric sensing device is prepared from the cellulose nanocrystal composite gelatin hydrogel; and a new design thought is provided for construction of a high-performance bio-based electro-mechanical hydrogel piezoresistive-piezoelectric dual-sensing wearable device.

This invention provides a colloidal gold labeling method with improved sensitivity, its applications, and products, relating to the field of immunochromatography technology. The colloidal gold labeling method provided by this invention involves mixing a protein to be labeled, treated with a protein activator, with a colloidal gold solution for labeling reaction to obtain a gold-labeled protein. The protein activator includes a nonionic surfactant, a glycoprotectant, and a reducing agent. Through the synergistic effect of these components, the interactions between the gold-labeled conjugates are effectively reduced, preventing aggregation and improving the stability of the gold-labeled conjugates while protecting protein activity. The pH of the colloidal gold solution is 0.3-0.8 lower than the isoelectric point of the protein to be labeled. Under these conditions, the gold-labeled conjugates formed have good stability and high labeling efficiency. This method is simple to operate, the prepared gold-labeled conjugates have high labeling efficiency and good stability, and the prepared reagent kit has high sensitivity and is less prone to missed detections.

Embodiments described herein relate to a device or apparatus for isoelectric aggregation precipitation of proteins in a solution on a horizontal plane, an apparatus and method for separating and precipitating an analyte of interest from a sample by sequentially adjusting the pH of the solution and pooling and separating the analyte of interest according to corresponding isoelectric points of the analyte of interest. The apparatus and method include subjecting a sample to fluid kinematics resting on a horizontal plane, applying an electric field parallel to the horizontal plane through an anode and a cathode on both sides of the sample, and then pooling and precipitating an analyte fraction of interest according to their respective isoelectric point movement.

The application discloses an ionic liquid functionalized eggshell membrane protein material and a preparation method and application thereof, and belongs to the technical field of biological piezoelectric materials. The eggshell membrane is pretreated and then grinded into powder; the eggshell membrane powder is treated with a NaOH solution and then cleaned to neutral; the eggshell membrane powder is dissolved in an aqueous solution of 3-mercaptopropionic acid and acetic acid to react, the pH is adjusted to an isoelectric point, and a precipitate is collected and dried to obtain soluble eggshell membrane; the soluble eggshell membrane is added into ionic liquid and fully stirred and dissolved to obtain an eggshell membrane protein solution; dialysis and freeze-drying are performed to obtain ionic liquid functionalized eggshell membrane protein; and the ionic liquid functionalized eggshell membrane protein is redissolved in an aqueous solution, subjected to static defoaming, dried, and immersed in anhydrous ethanol for cross-linking to obtain an ionic liquid functionalized eggshell membrane protein film. The eggshell membrane protein film prepared by the application has good mechanical properties, high thermal stability and piezoelectricity, and the degradable protein material can be applied to the fields of biological tissue engineering, intelligent sensing and energy collection.

The invention relates to physically stable compositions in the form of an injectable aqueous solution, having a pH between 6.0 and 8.0, comprising at least: a) a basal insulin having an isoelectric point (pI) between 5.8 and 8.5 and b) a co-polyamino acid bearing carboxylate charges and at least one hydrophobic radical.

Described herein is a bias-free high-throughput and high-yield continuous isoelectric fractionation (CIF) nanocarrier fractionation technique based on distinct isoelectric points. The nanocarrier fractionation platform is enabled by a robust and tunable linear pH profile provided by water-splitting at a bipolar membrane and stabilized by flow without ampholytes.