214 results about "Isoelectric point" patented technology

Provided herein are bispecific antibodies having modifications that enable greater developability and manufacturability. In certain instances, such bispecific antibodies comprise common light chain bispecific antibodies that bind CD38 and CD19, having reduced isoelectric focusing, improved hydrophobic interaction chromatography retention, and effective targeting of cells expressing CD19 and CD38. Also provided are methods of reducing an experimental isoelectric point of bispecific antibodies that bind CD19 and CD38.

The present invention discloses an injectable human collagen soft tissue filling material and a preparation method thereof, belonging to the technical field of biomedical materials. The injectable human collagen soft tissue filling material comprises pretreated recombinant human collagen and an osmotic pressure regulator, and the injectable human collagen soft tissue filling material is in an isotonic state; the pretreatment of the recombinant human collagen is processed by isoelectric precipitation and centrifugal separation process; the preparation method thereof comprises filtering and sterilizing the raw materials, pretreatment, and homogenizing the pretreated recombinant human collagen and the osmotic pressure regulator. The injectable human collagen soft tissue filling material of the present invention is mainly human collagen, has a large molecular weight and a triple helix structure, and has a uniform particle size distribution, which can play a filling and supporting effect; the preparation process thereof is simple and convenient, without special processing technology, and will not introduce toxic and harmful residual substances, so that the product performance is stable.

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 relates to a mussel bionic adhesive material based on oligopeptide modified polyglutamic acid, and a preparation method and application thereof, and belongs to the field of bionic bio-based materials. The preparation method comprises the following steps: firstly, synthesizing tyrosine-containing oligopeptide through protease catalysis, and modifying the oligopeptide onto a polyglutamic acid skeleton to obtain a bionic polymer precursor; meanwhile, polyglutamic acid is modified by cysteine groups, so that a bionic high polymer material with reducibility is synthesized, and a required reducibility reaction environment is provided. The preparation method comprises the following steps: uniformly mixing the polyglutamic acid and the precursor, activating tyrosine in the precursor in a reducing environment by using tyrosinase, converting the tyrosine into dopa to finally obtain a bionic adhesive material solution, and adjusting the pH value of the solution to be close to an isoelectric point of the polyglutamic acid to realize self-assembly to form the adhesive. The adhesive prepared by the preparation method disclosed by the invention shows excellent adhesion performance and also shows good biocompatibility.

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.

A qualitative or quantitative test method to detect a substance to be detected contained in a specimen, the test method including a preparation step of preparing a test sample from the specimen, and a test step of testing at least part of the test sample with a reagent to detect each of a first substance to be detected and a second substance to be detected, in which the first substance to be detected has an isoelectric point of 10.0 or more, and in any one or both of the preparation step and the test step, the first substance to be detected is brought into contact with any one or both of a glass-made member and a nitrocellulose-made member in the presence of a cationic substance. In this test method, two or more substances to be detected including a substance having an isoelectric point of 10.0 or more can be detected with high sensitivity using the same specimen while suppressing a decrease in measurement sensitivity.

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 provides an extracellular vesicle marker separation-free detection method based on nanoparticle enhancement, and belongs to the technical field of detection methods, the method comprises the following steps: preparing gold nanoparticles with the surface modified with a first antibody, the first antibody being used for specific recognition of an extracellular vesicle surface marker; determining the particle size distribution of the gold nanoparticles by adopting a dynamic light scattering method, and determining the surface potentials and surface isoelectric points of the gold nanoparticles by adopting a potentiostat; adopting a transmission electron microscope to characterize the morphology of the screened gold nanoparticles; co-modifying polyethylene glycol molecules on the surfaces of the gold nanoparticles to form an anti-interference layer; mixing the gold nanoparticles with uniform morphology with a sample to be detected; adding a second antibody into the mixed system; distinguishing signals of the binding-state second antibody and the free-state second antibody through fluorescence lifetime analysis; preparing an extracellular vesicle standard substance, and obtaining a standard curve and a system response curve; the optimal detection condition is determined by solving the detection system optimization equation set, and separation-free detection is carried out.

An anti-rabies virus neutralizing antibody and preparation and a use thereof. Provided is an anti-rabies virus neutralizing antibody, comprising a heavy chain variable region SEQ ID NO. 1-SEQ ID NO. 3, a light chain variable region SEQ ID NO. 4-SEQ ID NO. 5, and GAS. The anti-rabies virus neutralizing antibody has good neutralizing activity; a high isoelectric point provides advantages in the stability of antibody formulations; a high Tm value indicates good thermal stability; strong affinity with recombinant rabies virus glycoproteins shows promise for the mass production of rabies virus neutralizing antibodies, providing technical support for the preparation of low-cost, safe, and effective rabies passive immune formulations.

The invention discloses cellulose nanocrystal Pickering emulsion gel with stable protein hydrophobic modification and a preparation method of the cellulose nanocrystal Pickering emulsion gel, oil-in-water type emulsion gel is prepared and formed under the shearing action based on cellulose nanocrystals (CNCs) coated with protein or protein sodium salt with an isoelectric point in a range of 4-6, so that a stable gel network structure is formed; by adjusting conditions of different protein coating proportions, particle concentrations and internal phase proportions, the emulsion gel can obtain different processability, and the emulsion gel based on different performance differences has good application flexibility in 3D printing. The main materials are safe in source and have good biocompatibility and biodegradability, the modification method is green and safe, and the prepared emulsion gel can be used as a food 3D printing base material or a nutrient substance loading material.

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 present invention relates to the technical field of waste recovery, and provides a method for preparing a hemihydrate gypsum powder from phosphogypsum by means of an atmospheric salt solution process, and a hemihydrate gypsum powder. The method comprises: preparing a slurry from a mixed liquid of a salt and a crystal modifier and purified phosphogypsum, wherein the crystal modifier is a betaine compound with pH responsiveness; and adjusting the pH value of the slurry on the basis of the isoelectric point of the crystal modifier and the required length-diameter ratio of hemihydrate gypsum crystals, subjecting the slurry to a constant-temperature dynamic reaction, and filtering same, thereby obtaining a hemihydrate gypsum powder, wherein when the pH value of the slurry is greater than the isoelectric point of the crystal modifier, the length-diameter ratio of the hemihydrate gypsum crystals increases, and when the pH value of the slurry is less than the isoelectric point of the crystal modifier, the length-diameter ratio of the hemihydrate gypsum crystals decreases. By using the betaine compound as the crystal modifier, hemihydrate gypsum crystals with different length-diameter ratios can be obtained by adjusting the pH value of the slurry, and therefore the regulation and control of the crystal morphology of hemihydrate gypsum are achieved and exhibit a certain pattern.

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 invention discloses a method for rapidly and efficiently extracting ovotransferrin in egg white, which comprises the following steps: (1) pre-treating egg white, namely treating egg white liquid through an ultrasonic composite high-voltage pulse electric field, so that the thick protein is thinned, the viscosity is further reduced, molecules are dispersed, the egg white liquid is prevented from being diluted by adding water in the subsequent process, and the production efficiency is favorably improved; (2) removal of ovomucin and ovalbumin: removing the ovomucin and ovalbumin by an isoelectric precipitation method combined with a PEG precipitation method; (3) preparation of ovotransferrin; (4) separating an ovotransferrin crude product; and (5) purifying the ovotransferrin crude product. According to the method disclosed by the invention, high-yield and high-purity ovotransferrin is rapidly and efficiently prepared, and the method is simple, relatively low in cost and suitable for large-scale industrialization.

The invention discloses a large-through-flow varistor and a preparation method thereof, and belongs to the technical field of varistors, the varistor is prepared from the following raw materials: 93 to 96 mol percent of modified ZnO, 1.2 to 1.6 mol percent of Bi2O3, 0.5 to 1.5 mol percent of Co3O4, 0.3 to 0.8 mol percent of Mn2O3, 1.0 to 3.0 mol percent of Sb2O3, 0.3 to 0.8 mol percent of NiO and 0.05 to 0.3 mol percent of Li2CO3; a silane coupling agent with a fluorinated quaternary ammonium salt structure is adopted to modify the surface of ZnO, and the quaternary ammonium salt structure improves the isoelectric point of ZnO, so that ZnO is positively charged at a relatively high pH value, the interaction with an anionic dispersant is enhanced, and the effect of the anionic dispersant on slurry is improved; f <-> introduced by the silane coupling agent is uniformly dispersed on the surface of ZnO, during subsequent sintering, Li < + > is used as a diffusion carrier, the migration rate of F <-> in crystal lattices can be improved through the synergistic effect of Li < + > and F <->, and the property of the ZnO varistor is enhanced by introducing Li < + > and F <->.

The invention discloses a method for detecting a charge variant of a monoclonal antibody. The method comprises the following steps: preparing a monoclonal antibody to be detected into a test solution; the test solution comprises a monoclonal antibody to be detected, a methylcellulose solution, urea, amino acid, an ampholyte carrier and an isoelectric point marker; detecting the test solution by adopting a full-column imaging capillary isoelectric focusing method, and determining the content percentage of the charge variant of the monoclonal antibody to be detected according to an isoelectric focusing map; wherein the isoelectric point of the amino acid is similar to the boundary isoelectric point of a main peak and an alkali peak in an isoelectric focusing map of the monoclonal antibody to be detected. According to the method, the separation degree between the main peak and the alkali peak of the to-be-detected sample can be remarkably improved. The sensitivity is good, the precision is high, and while the separation degree of a main peak and an alkali peak is improved in a targeted manner, the separation degree and proportion of an acid peak and the main peak, the isoelectric point of a sample and the like are basically not influenced.

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 present invention belongs to the technical field of leather processing and manufacturing, and discloses an application of a modified enzyme in treating animal skins and leather. The application of the modified enzyme in treating animal skins, wherein the modified enzyme is a modified protease, and the absolute value of the difference between its isoelectric point and the pH value of the animal skin treatment process is not greater than 0.5. The present invention can improve the transfer rate of the protease in the skin, shorten the action time of the protease on the grain layer of the animal skin, and improve the uniformity of the action of the protease on the skin. The present invention can solve the technical problems of easy surface damage or loose surface when using protease to treat animal skins, and improve the quality of leather products.

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.