180 results about "Isoelectric focusing" patented technology

The invention relates generally to compositions and methods for altering the isoelectric point of an antibody, and in some cases, resulting in improved plasma pharmacokinetics, e.g. increased serum half-life in vivo.

The invention relates generally to compositions and methods for altering the isoelectric point of an antibody, and in some cases, resulting in improved plasma pharmacokinetics, e.g. increased serum half-life in vivo.

An apparatus and method are disclosed for the precise selection and extraction of a selected analyte in a focused zone produced by isoelectric focusing performed in micro-channels. A cross-channel microfluidic device comprises a sample mixture introduction and separation channel and an extraction channel, which are in fluid communication with each other at a point of intersection. Means are provided for selectively moving the pattern of separated zones following cIEF to the intersection point, and means are provided for applying an extraction pressure to direct a single zone containing a selected analyte into and then out of the extraction channel for collection.

Methods are described for modifying the isoelectric point of an antibody while retaining its antigen-binding activity, comprising modifying the charge of at least one exposable amino acid residue on the surface of the complementarity determining region (CDR). The disclosure also provides methods for purifying multispecific antibodies, comprising modifying isoelectric point, and methods for improving the plasma pharmacokinetics of antibodies with a modified isoelectric point. The disclosure further provides antibodies with a modified isoelectric point, pharmaceutical compositions comprising the antibodies as an active ingredient, and methods for producing the antibodies and compositions.

The invention relates generally to compositions and methods for altering the isoelectric point of an antibody, and in some cases, resulting in improved plasma pharmacokinetics, e.g. increased serum half-life in vivo.

Improved apparatus is disclosed for carrying out axially illuminated laser induced fluorescence whole-column imaging detection in the capillary isoelectric focusing of proteins. The separation capillary was made of low refractive index Teflon conditioned with methylcellulose to reduce electroosmotic flow and a small amount of high refractive index organic solvent (glycerol) was added to the sample mixture. It was found that an axially directed laser excitation beam was propagated essentially with total internal reflection, so that minimum interference arose from stray light or from scattering light originating from the wall of the capillary. With the naturally fluorescent protein R-phycoerythrin, a concentration detection limit LOD 10−11 M or mass LOD 10−17 Mo was obtained.

A separation module operates to fractionate or separate an analyte into fractions according to pI, i.e., pI bands, utilizing capillary isoelectric focusing (“CIEF”) within a first microchannel. The fractions are stacked to form plugs, the number of which is determined by a number of parallel second microchannels integrally connected to the first microchannel, into which the fractions are directed according to the buffer characteristics found in each of the individual microchannels. Within the microchannels the plugs are separated into proteins according to a different chemical property, i.e., “m / z,” utilizing capillary electrophoresis (“CE”).

A separation module operates to fractionate or separate an analyte into fractions according to pI, i.e., pI bands, utilizing capillary isoelectric focusing (“CIEF”) within a first microchannel. The fractions are stacked to form plugs, the number of which is determined by a number of parallel second microchannels integrally connected to the first microchannel, into which the fractions are directed according to the buffer characteristics found in each of the individual microchannels. Within the microchannels the plugs are separated into proteins according to a different chemical property, i.e., “m / z,” utilizing capillary electrophoresis (“CE”).

The present invention provides methods for efficient and concomitant recovery of multiple chaperone proteins and / or chaperone protein complexes from a limited sample source. Disclosed are methods involving the use of Free Solution Iso-Electric Focusing (FS-IEF) which can enrich samples containing chaperone proteins and / or chaperone protein complexes from a given sample. The chaperone proteins can be, but are not restricted to calreticulin, gp96, hsp86, hsp84, hsp70, hsp60 and hsp40. The invention also provides methods of recovering chaperone protein complexes for the preparation of vaccines containing chaperone complexes.

A method and apparatus are provided for performing capillary isoelectric focusing followed by mobilization of the focused zones by induced hydrodynamic flow or chemical mobilization. These two dimensions of separation are integrated with real-time whole-channel electrophoresis detection and automatic sample injection to achieve a separation resolution superior to that obtainable using known orthogonal capillary two dimensional arrangements.

Disclosed herein is an apparatus for the separation of proteins, comprising a capillary isoelectric focusing unit (2) for primarily separating protein samples on the basis of pi; and a hollow fiber flow field flow fractionation unit (4), connected to one side of the capillary isoelectric focusing unit (2), for secondarily separating the protein samples. The apparatus allows proteins to be separated on the basis of pi and molecular weight without denaturation and can further be applied for the identification of proteins in conjunction with nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry after enzymatic digestion of the protein fractions.

The invention provides a novel solution isoelectric focusing device and method that can reproducibly fractionate charged molecules into well-defined pools. This approach can be applied to mixtures of charged molecules, such as eukaryotic proteome samples where reproducible resolution and quantitation of greater than 10,000 protein components is feasible.

Provided are a method and apparatus for measuring an isoelectric point using a field effect transistor. The method includes providing a field effect transistor including a substrate, source and drain electrodes disposed on the substrate and spaced apart from each other, and a channel region between the source and drain electrodes, providing a first electrolyte solution having a first concentration to the channel region of the field effect transistor and measuring a first current value of the channel region between the source and drain electrodes, providing a second electrolyte solution having a second concentration greater than the first concentration and measuring a second current value of the channel region between the source and drain electrodes, and determining the isoelectric point of the field effect transistor or a material disposed on the field effect transistor using a difference between the first and second current values.

A process for preparing taurine includes preparing the mixture containing taurine from ethanolamine by cyclc method, separating out inorganic salt by feedback type elecric dialysis with ion membrane, crystallizing taurine in solution, and using the residual mother liquid for next reduction reaction. Its advantages are high output rate and high current efficiency.

The microflow control chip for protein analysis features that it consists of four basic units connected successively with the sample outlet of the upper basic unit being connected to the sample inletof the next basic unit. They are the first protein isoelectric focusing separation unit; the second protein screening electrophoresis unit with organic polymer selected from cellulose and agarose asscreening medium; the third protein proteinase enzymolyzing unit with specific proteinase bonded to the inner wall or specific proteinase stuffing filled; and the fourth interface unit to convey the enzymolysis product of protein to mass spectral analysis. Using the chip of the present invention in protein analysis can obtain great amount of information in short time and through simple operation.

Methods and apparatus are provided to resolve analytes within a fluid path using isoelectric focusing, gel electrophoresis, or other separation means. Materials within the fluid path that are compatible with these separation means are used to attach resolved analytes to the wall of the fluid path. Attachment results from a triggerable event such as photoactivation, thermal activation, or chemical activation. In accordance with a further aspect of the present invention, the material in the capillary may also be disrupted, by either the triggerable event or a subsequent event such as melting or photocleavage. Thus, an open lumen or porous structure may be created within the fluid path, allowing unbound analyte materials to be washed from the fluid path, and detection agents to be washed into the fluid path. The separation-compatible materials may be polymerizable monomers, gels, entangled polymers or other materials.

A self-assembled engineered lattice of nanometer-scale silica particles, or other suitable particles generally resembling regularly-sized spheres, is configured in a separation bed for electrophoresis, isoelectric focusing, chromatography, or other voltage-induced separation of analytes. After separation, the analytes are immobilized on the separation bed and then ionized using matrix-assisted laser desorption / ionization (MALDI) for use with a mass spectrometer. The nanoparticles can be coated with polymers that activate to immobilize the analytes or assist with MALDI. The separation can occur in two dimensions.

The invention discloses a clam bioactive peptide and its extraction method and use. The clam bioactive peptide has an N-tail end sequence of TRGIDEIQNT GGGGTRR, an isoelectric point of 8.79 and molecular weight of 18KDa. The clam bioactive peptide can promote macrophage phagocytosis activity and splenic lymphocyte propagation capability of an immunization system, has pharmacological effects of improving immunity, can be used for preparation of a drug or a health food for improving immunity and has potential of exploitation of novel immunopotentiation drugs.

Provided herein are IEF focusing methods for determining the number of drug molecules present in at least one antibody-drug conjugate (ADC) species subpopulation. In one embodiment, the method comprises performing free solution isoelectric focusing on a sample comprising at least one ADC species, to obtain a focused sample. The absorbance of the sample at two different wavelengths is then measured, for example, over a range of pI values. Absorbance values at the two different wavelengths are compared at at least one corresponding pI value, where the at least one corresponding pI value is the pI of the ADC subpopulation. The number of drug molecules in the at least one ADC species subpopulation is then determined based on the comparison. The methods provided herein can also be used to determine the number of specific binding pair members bound to its target specific binding pair member.

An electrophoresis apparatus for the simultaneous electrophoretic separation of a plurality of component mixtures using a disposable tray having a plurality of parallel troughs shaped to retain an elongate strip of isoelectric focusing medium and sufficient liquid to immerse the elongate strip. A frame is provided to retain the tray in a horizontal position using a pair of rotatably mounted support members moving between an open and closed position. Support members are also connected to a plurality of electrodes aligned with each of the troughs so that the electrodes are positioned clear of the troughs in the open position and positioned in the troughs when in the closed position.

Isoelectric focusing gels are cast in a rod-shaped casting mold split longitudinally into two halves, each half having a half-circle profile so that the combined halves form a completed mold that is tubular in shape with a circular cross section. Flat grooves are cut into the flat contacting surfaces of each of the mold halves, the grooves in direct opposition to one another to form a chamber of rectangular cross section extending the full length of the mold and open at both ends. One groove receives a flexible backing strip for the gel and the other serves as the casting chamber for the gel. Once the gel is cast in this mold, isoelectric focusing can be performed as if the gel were a tube gel, and the two mold halves are then readily separated to permit removal of the gel and its transfer if desired to a second dimension separation.

A method for identifying phosphoprotein, which comprises: subjecting a sample protein to two-dimensional electrophoresis; dephosphorylating the sample protein with phosphatase; once again performing the two-dimensional electrophoresis under the same conditions; and detecting the spot that migrates to the alkaline side of the isoelectric focusing as the phosphoprotein is provided as a convenient method for identifying phosphoprotein with high accuracy.

Botanical extracts and derivative compositions are described for activating or inhibiting the formation and development of bacterial biofilms. Gymnemic acids and other associated saponins are isolated from botanical extractions of the Gymnema sylvestre plant and are used to modulate bacterial biofilm virulence, especially biofilms associated with Staphylococcus aureus. Gurmarin, a polypeptide isolated from botanical extractions of the Gymnema sylvestre plant are used to inhibit biofilm formation, especially biofilms associated with Staphylococcus aureus. Methods for isolating gurmarin (as well as other peptides from botanical extracts) are described using isoelectric focusing separation techniques. Various uses for both research and health care concerns are described for the biofilm activators (modulators) and for the biofilm inhibitor.

The present invention generally relates to devices and methods for the separation of species, including biological species. Some embodiments involve the use of free flow isoelectric focusing (FF-IEF) devices in the separation of a mixture of species. Various device configurations and / or features may enhance the performance of the devices, providing faster and more efficient devices and methods for separating mixtures of species with high resolution. In some embodiments, separation of a mixture of species may be achieved with high resolution and with short sample residence times. Such devices may provide simplified, inexpensive, and optionally disposable devices for the separation of chemical and biological species and may optionally be integrated with orthogonal separation techniques, such as SDS-PAGE or capillary electrophoresis.

The invention relates to a method for separating, enriching and identifying macromolecular weight protein, belonging to the field of biochemical analysis. In the invention, a mixed gel of low-melting point agarose and polyacrylamide is used as an electrophoresis supporting medium, and an analysis path of gel slab electrophoresis combined with efficient liquid-phase chromatography - electrical spraying mass spectrum identification and another analysis path of solid-phase gradient pH dry adhesive tape isoelectro-focusing combined with gel slab electrophoresis separation - matrix auxiliary laser desorption ionization mass spectrum identification are collectively used to separate and identify the macromolecular weight protein. The gel provided by the invention has the advantages of big aperture, high mechanical strength, high resolution ratio, good repeatability and good mass spectrum compatibility; the macromolecular weight separation scope can be adjusted based on different component proportions; and protein with the molecular weight interval above 100kDa can be selectively separated with repeatability RSD up to 7.6%, thereby obviously improving the identification ratio. The method is an effective tool for separating the macromolecular weight protein, which can be applied to proteomics study field.

The invention discloses a dielectrophoresis method for proteins of malus plants. The steps of the method are as follows: 1) plant materials are ground in liquid nitrogen and are added with an acetone solution which is pre-cooled at a temperature of 20 DEG C below zero and contains a trichloroacetic acid with the concentration of 10g / 100ml and beta-mercaptoethanol with the concentration of 0.07ml / 100ml and continuously ground to be the homogenate, and the homogenate stands at a temperature of 20 DEG C below zero for 1 hour and centrifuged by the rotary speed of 12000rpm for 15 minutes, and the precipitation is kept; 2) the precipitation is added with an acetone solution which contains the beta-mercaptoethanol with the concentration of 0.07ml / 100ml and the volume of which is 4 times of the volume of the precipitation, and the mixed solution is evenly mixed and stands at a temperature of 20 DEG C below zero for 1 hour, and centrifuged by the rotary speed of 12000rpm for 15 minutes, and the precipitation is kept; 3) the step 2 is repeated for 6 times, and total proteins are obtained; 4) total proteins obtained from the step 3 undergo the electric focusing electrophoresis, and the sample volume of proteins is of 300ug / 170mm adhesive tape, and the polyacrylamide gel electrophoresis is conducted, and the silver dyeing is conducted after the electrophoresis.

A plurality of particles of from about 5 nm to 100 μm possessing predetermined isoelectric points in the pH range from about 2.5 to 11 is used in a method of detection of a plurality of analytes, wherein the isoelectric particles of each isoelectric point further contain a label and a member of a binding pair capable of interacting with a selected analyte. The particles that formed specific binding pairs are recovered and separated by isoelectric focusing, followed by the detection of the labels associated with the particles. A flow cytometer may be used as a detector of the isoelectric particles.

The invention discloses the main sensitization protein of humulus pollen which can be separated and obtained from the humulus pollen and combined with over 89 percent of serological specificity IgE of patients allergic to humulus pollen. The apparent molecular weight of the protein measured by SDS-PAGE is about 12kDa, the isoelectric point is 4.7 and the N-terminal sequence is NH4<+>-MDNPFENGMKA-COO<->. The separation and purification of the protein lay the foundation for realizing the standization of the allergenic preparations of the protein.

Disclosed is an agent for digesting a protein highly resistant to denaturation and degradation, comprising as an active ingredient an enzyme exhibiting an activity of digesting a protein highly resistant to denaturation and degradation and having the following properties: (a) activity and substrate specificity: hydrolyzing a peptide bond of a protein highly resistant to denaturation and degradation; (b) molecular weight: 31,000 (determined by SDS-polyacrylamide gel electrophoresis using a homogeneous gel having a gel concentration of 12%); (c) isoelectric point: pI 9.3 (determined by polyacrylamide gel isoelectric focusing electrophoresis); (d) optimum pH: pH 9.0 to 10.0; and (e) optimum temperature for activity: 60 to 70° C.