Isoelectric Point: The pH in solutions of proteins and related compounds at which the dipolar ions are at a maximum.Isoelectric Focusing: Electrophoresis in which a pH gradient is established in a gel medium and proteins migrate until they reach the site (or focus) at which the pH is equal to their isoelectric point.Molecular Weight: The sum of the weight of all the atoms in a molecule.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Amino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Chromatography, Gel: Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.Chromatography, Ion Exchange: Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Kinetics: The rate dynamics in chemical or physical systems.Electrophoresis, Gel, Two-Dimensional: Electrophoresis in which a second perpendicular electrophoretic transport is performed on the separate components resulting from the first electrophoresis. This technique is usually performed on polyacrylamide gels.Chromatography, Affinity: A chromatographic technique that utilizes the ability of biological molecules to bind to certain ligands specifically and reversibly. It is used in protein biochemistry. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Chromatography: Techniques used to separate mixtures of substances based on differences in the relative affinities of the substances for mobile and stationary phases. A mobile phase (fluid or gas) passes through a column containing a stationary phase of porous solid or liquid coated on a solid support. Usage is both analytical for small amounts and preparative for bulk amounts.Chromatography, DEAE-Cellulose: A type of ion exchange chromatography using diethylaminoethyl cellulose (DEAE-CELLULOSE) as a positively charged resin. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Immunodiffusion: Technique involving the diffusion of antigen or antibody through a semisolid medium, usually agar or agarose gel, with the result being a precipitin reaction.Chemistry: A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.Chemical Phenomena: The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.Enzyme Stability: The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat.Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Electrophoresis, Disc: Electrophoresis in which discontinuities in both the voltage and pH gradients are introduced by using buffers of different composition and pH in the different parts of the gel column. The term 'disc' was originally used as an abbreviation for 'discontinuous' referring to the buffers employed, and does not have anything to do with the shape of the separated zones.Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.Macromolecular Substances: Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Electrophoresis: An electrochemical process in which macromolecules or colloidal particles with a net electric charge migrate in a solution under the influence of an electric current.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Hot Temperature: Presence of warmth or heat or a temperature notably higher than an accustomed norm.Carbohydrates: The largest class of organic compounds, including STARCH; GLYCOGEN; CELLULOSE; POLYSACCHARIDES; and simple MONOSACCHARIDES. Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n.Chemistry, Physical: The study of CHEMICAL PHENOMENA and processes in terms of the underlying PHYSICAL PHENOMENA and processes.Physicochemical Phenomena: The physical phenomena describing the structure and properties of atoms and molecules, and their reaction and interaction processes.Immunoelectrophoresis: A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Trypsin: A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Glycoside HydrolasesSpectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Drug Stability: The chemical and physical integrity of a pharmaceutical product.Cations, Divalent: Positively charged atoms, radicals or groups of atoms with a valence of plus 2, which travel to the cathode or negative pole during electrolysis.Protease Inhibitors: Compounds which inhibit or antagonize biosynthesis or actions of proteases (ENDOPEPTIDASES).Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Bacterial Proteins: Proteins found in any species of bacterium.Ammonium Sulfate: Sulfuric acid diammonium salt. It is used in CHEMICAL FRACTIONATION of proteins.Fractional Precipitation: A method which uses specific precipitation reactions to separate or collect substances from a solution.Hydroxyapatites: A group of compounds with the general formula M10(PO4)6(OH)2, where M is barium, strontium, or calcium. The compounds are the principal mineral in phosphorite deposits, biological tissue, human bones, and teeth. They are also used as an anticaking agent and polymer catalysts. (Grant & Hackh's Chemical Dictionary, 5th ed)Metals: Electropositive chemical elements characterized by ductility, malleability, luster, and conductance of heat and electricity. They can replace the hydrogen of an acid and form bases with hydroxyl radicals. (Grant & Hackh's Chemical Dictionary, 5th ed)Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Neuraminidase: An enzyme that catalyzes the hydrolysis of alpha-2,3, alpha-2,6-, and alpha-2,8-glycosidic linkages (at a decreasing rate, respectively) of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid, and synthetic substrate. (From Enzyme Nomenclature, 1992)Peptide Mapping: Analysis of PEPTIDES that are generated from the digestion or fragmentation of a protein or mixture of PROTEINS, by ELECTROPHORESIS; CHROMATOGRAPHY; or MASS SPECTROMETRY. The resulting peptide fingerprints are analyzed for a variety of purposes including the identification of the proteins in a sample, GENETIC POLYMORPHISMS, patterns of gene expression, and patterns diagnostic for diseases.Endopeptidases: A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.Immunochemistry: Field of chemistry that pertains to immunological phenomena and the study of chemical reactions related to antigen stimulation of tissues. It includes physicochemical interactions between antigens and antibodies.ChitinasePlant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Peptide Hydrolases: Hydrolases that specifically cleave the peptide bonds found in PROTEINS and PEPTIDES. Examples of sub-subclasses for this group include EXOPEPTIDASES and ENDOPEPTIDASES.Trypsin Inhibitors: Serine proteinase inhibitors which inhibit trypsin. They may be endogenous or exogenous compounds.Sodium Dodecyl Sulfate: An anionic surfactant, usually a mixture of sodium alkyl sulfates, mainly the lauryl; lowers surface tension of aqueous solutions; used as fat emulsifier, wetting agent, detergent in cosmetics, pharmaceuticals and toothpastes; also as research tool in protein biochemistry.Chemical Precipitation: The formation of a solid in a solution as a result of a chemical reaction or the aggregation of soluble substances into complexes large enough to fall out of solution.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Pseudomonas: A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in nature. Some species are pathogenic for humans, animals, and plants.Solubility: The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Cross Reactions: Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.Xylosidases: A group of enzymes that catalyze the hydrolysis of alpha- or beta-xylosidic linkages. EC 3.2.1.8 catalyzes the endo-hydrolysis of 1,4-beta-D-xylosidic linkages; EC 3.2.1.32 catalyzes the endo-hydrolysis of 1,3-beta-D-xylosidic linkages; EC 3.2.1.37 catalyzes the exo-hydrolysis of 1,4-beta-D-linkages from the non-reducing termini of xylans; and EC 3.2.1.72 catalyzes the exo-hydrolysis of 1,3-beta-D-linkages from the non-reducing termini of xylans. Other xylosidases have been identified that catalyze the hydrolysis of alpha-xylosidic bonds.Bacillus: A genus of BACILLACEAE that are spore-forming, rod-shaped cells. Most species are saprophytic soil forms with only a few species being pathogenic.DNA, Complementary: Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.Immune Sera: Serum that contains antibodies. It is obtained from an animal that has been immunized either by ANTIGEN injection or infection with microorganisms containing the antigen.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Carboxylic Ester Hydrolases: Enzymes which catalyze the hydrolysis of carboxylic acid esters with the formation of an alcohol and a carboxylic acid anion.Sequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.Ultracentrifugation: Centrifugation with a centrifuge that develops centrifugal fields of more than 100,000 times gravity. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)beta-Lactamases: Enzymes found in many bacteria which catalyze the hydrolysis of the amide bond in the beta-lactam ring. Well known antibiotics destroyed by these enzymes are penicillins and cephalosporins.Spectrophotometry, Ultraviolet: Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.Immunoelectrophoresis, Two-Dimensional: Immunoelectrophoresis in which a second electrophoretic transport is performed on the initially separated antigen fragments into an antibody-containing medium in a direction perpendicular to the first electrophoresis.Polysaccharide-Lyases: A group of carbon-oxygen lyases. These enzymes catalyze the breakage of a carbon-oxygen bond in polysaccharides leading to an unsaturated product and the elimination of an alcohol. EC 4.2.2.Cytosol: Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.Peptides: Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.CephalosporinaseSequence Analysis: A multistage process that includes the determination of a sequence (protein, carbohydrate, etc.), its fragmentation and analysis, and the interpretation of the resulting sequence information.Sulfhydryl Reagents: Chemical agents that react with SH groups. This is a chemically diverse group that is used for a variety of purposes. Among these are enzyme inhibition, enzyme reactivation or protection, and labelling.Rats, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.Xylans: Polysaccharides consisting of xylose units.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Biological Assay: A method of measuring the effects of a biologically active substance using an intermediate in vivo or in vitro tissue or cell model under controlled conditions. It includes virulence studies in animal fetuses in utero, mouse convulsion bioassay of insulin, quantitation of tumor-initiator systems in mouse skin, calculation of potentiating effects of a hormonal factor in an isolated strip of contracting stomach muscle, etc.Chymotrypsin: A serine endopeptidase secreted by the pancreas as its zymogen, CHYMOTRYPSINOGEN and carried in the pancreatic juice to the duodenum where it is activated by TRYPSIN. It selectively cleaves aromatic amino acids on the carboxyl side.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Serine Endopeptidases: Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.Glucans: Polysaccharides composed of repeating glucose units. They can consist of branched or unbranched chains in any linkages.EsterasesHexosaminidases: Enzymes that catalyze the hydrolysis of N-acylhexosamine residues in N-acylhexosamides. Hexosaminidases also act on GLUCOSIDES; GALACTOSIDES; and several OLIGOSACCHARIDES.Recombinant Proteins: Proteins prepared by recombinant DNA technology.beta-Glucosidase: An exocellulase with specificity for a variety of beta-D-glycoside substrates. It catalyzes the hydrolysis of terminal non-reducing residues in beta-D-glucosides with release of GLUCOSE.Chromatography, Agarose: A method of gel filtration chromatography using agarose, the non-ionic component of agar, for the separation of compounds with molecular weights up to several million.Cations: Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.Carboxypeptidases: Enzymes that act at a free C-terminus of a polypeptide to liberate a single amino acid residue.PeroxidasesLactoglobulins: Globulins of milk obtained from the WHEY.Phenylmethylsulfonyl Fluoride: An enzyme inhibitor that inactivates IRC-50 arvin, subtilisin, and the fatty acid synthetase complex.Durapatite: The mineral component of bones and teeth; it has been used therapeutically as a prosthetic aid and in the prevention and treatment of osteoporosis.Blood Proteins: Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization: A mass spectrometric technique that is used for the analysis of large biomolecules. Analyte molecules are embedded in an excess matrix of small organic molecules that show a high resonant absorption at the laser wavelength used. The matrix absorbs the laser energy, thus inducing a soft disintegration of the sample-matrix mixture into free (gas phase) matrix and analyte molecules and molecular ions. In general, only molecular ions of the analyte molecules are produced, and almost no fragmentation occurs. This makes the method well suited for molecular weight determinations and mixture analysis.Sequence Homology, Nucleic Acid: The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Alcohol Oxidoreductases: A subclass of enzymes which includes all dehydrogenases acting on primary and secondary alcohols as well as hemiacetals. They are further classified according to the acceptor which can be NAD+ or NADP+ (subclass 1.1.1), cytochrome (1.1.2), oxygen (1.1.3), quinone (1.1.5), or another acceptor (1.1.99).Urea: A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.Carbohydrate Dehydrogenases: Reversibly catalyze the oxidation of a hydroxyl group of carbohydrates to form a keto sugar, aldehyde or lactone. Any acceptor except molecular oxygen is permitted. Includes EC 1.1.1.; EC 1.1.2.; and 1.1.99.Chloromercuribenzoates: Chloride and mercury-containing derivatives of benzoic acid.Phospholipases: A class of enzymes that catalyze the hydrolysis of phosphoglycerides or glycerophosphatidates. EC 3.1.-.Glycosylation: The chemical or biochemical addition of carbohydrate or glycosyl groups to other chemicals, especially peptides or proteins. Glycosyl transferases are used in this biochemical reaction.Centrifugation, Isopycnic: A technique used to separate particles according to their densities in a continuous density gradient. The sample is usually mixed with a solution of known gradient materials and subjected to centrifugation. Each particle sediments to the position at which the gradient density is equal to its own. The range of the density gradient is usually greater than that of the sample particles. It is used in purifying biological materials such as proteins, nucleic acids, organelles, and cell types.Chickens: Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.MercaptoethanolCentrifugation, Density Gradient: Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Hemolymph: The blood/lymphlike nutrient fluid of some invertebrates.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Seeds: The encapsulated embryos of flowering plants. They are used as is or for animal feed because of the high content of concentrated nutrients like starches, proteins, and fats. Rapeseed, cottonseed, and sunflower seed are also produced for the oils (fats) they yield.Glucosidases: Enzymes that hydrolyze O-glucosyl-compounds. (Enzyme Nomenclature, 1992) EC 3.2.1.-.Bence Jones Protein: An abnormal protein with unusual thermosolubility characteristics that is found in the urine of patients with MULTIPLE MYELOMA.Sugar Alcohol Dehydrogenases: Reversibly catalyzes the oxidation of a hydroxyl group of sugar alcohols to form a keto sugar, aldehyde or lactone. Any acceptor except molecular oxygen is permitted. Includes EC 1.1.1.; EC 1.1.2. and EC 1.1.99.Electrophoresis, Starch Gel: Electrophoresis in which a starch gel (a mixture of amylose and amylopectin) is used as the diffusion medium.Protein Denaturation: Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.Genes, Bacterial: The functional hereditary units of BACTERIA.AmidohydrolasesAcetylglucosaminidase: A beta-N-Acetylhexosaminidase that catalyzes the hydrolysis of terminal, non-reducing 2-acetamido-2-deoxy-beta-glucose residues in chitobiose and higher analogs as well as in glycoproteins. Has been used widely in structural studies on bacterial cell walls and in the study of diseases such as MUCOLIPIDOSIS and various inflammatory disorders of muscle and connective tissue.Submandibular Gland: One of two salivary glands in the neck, located in the space bound by the two bellies of the digastric muscle and the angle of the mandible. It discharges through the submandibular duct. The secretory units are predominantly serous although a few mucous alveoli, some with serous demilunes, occur. (Stedman, 25th ed)Epitopes: Sites on an antigen that interact with specific antibodies.Geotrichum: A mitosporic Saccharomycetales fungal genus, various species of which have been isolated from pulmonary lesions. Teleomorphs include Dipodascus and Galactomyces.Oxidation-Reduction: A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).alpha-Amylases: Enzymes that catalyze the endohydrolysis of 1,4-alpha-glycosidic linkages in STARCH; GLYCOGEN; and related POLYSACCHARIDES and OLIGOSACCHARIDES containing 3 or more 1,4-alpha-linked D-glucose units.Oxidoreductases: The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)Adsorption: The adhesion of gases, liquids, or dissolved solids onto a surface. It includes adsorptive phenomena of bacteria and viruses onto surfaces as well. ABSORPTION into the substance may follow but not necessarily.Acetabularia: A genus of green algae found in the Mediterranean and other warm seas.Enzyme Induction: An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Pectins: High molecular weight polysaccharides present in the cell walls of all plants. Pectins cement cell walls together. They are used as emulsifiers and stabilizers in the food industry. They have been tried for a variety of therapeutic uses including as antidiarrheals, where they are now generally considered ineffective, and in the treatment of hypercholesterolemia.Chemical Fractionation: Separation of a mixture in successive stages, each stage removing from the mixture some proportion of one of the substances, for example by differential solubility in water-solvent mixtures. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Crystallization: The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.Arylsulfatases: Enzymes that catalyze the hydrolysis of a phenol sulfate to yield a phenol and sulfate. Arylsulfatase A, B, and C have been separated. A deficiency of arylsulfatases is one of the causes of metachromatic leukodystrophy (LEUKODYSTROPHY, METACHROMATIC). EC 3.1.6.1.Edetic Acid: A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Streptomyces: A genus of bacteria that form a nonfragmented aerial mycelium. Many species have been identified with some being pathogenic. This genus is responsible for producing a majority of the ANTI-BACTERIAL AGENTS of practical value.Polyporaceae: A family of bracket fungi, order POLYPORALES, living in decaying plant matter and timber.Protein Processing, Post-Translational: Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.Immunosorbent Techniques: Techniques for removal by adsorption and subsequent elution of a specific antibody or antigen using an immunosorbent containing the homologous antigen or antibody.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.SulfatasesUltrafiltration: The separation of particles from a suspension by passage through a filter with very fine pores. In ultrafiltration the separation is accomplished by convective transport; in DIALYSIS separation relies instead upon differential diffusion. Ultrafiltration occurs naturally and is a laboratory procedure. Artificial ultrafiltration of the blood is referred to as HEMOFILTRATION or HEMODIAFILTRATION (if combined with HEMODIALYSIS).Immunoblotting: Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.Thermus: Gram-negative aerobic rods found in warm water (40-79 degrees C) such as hot springs, hot water tanks, and thermally polluted rivers.Penicillinase: A beta-lactamase preferentially cleaving penicillins. (Dorland, 28th ed) EC 3.5.2.-.Physarum: A genus of protozoa, formerly also considered a fungus. Characteristics include the presence of violet to brown spores.Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase: A group of related enzymes responsible for the endohydrolysis of the di-N-acetylchitobiosyl unit in high-mannose-content glycopeptides and GLYCOPROTEINS.Xylan Endo-1,3-beta-Xylosidase: A xylosidase that catalyses the random hydrolysis of 1,3-beta-D-xylosidic linkages in 1,3-beta-D-xylans.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Circular Dichroism: A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Sulfhydryl Compounds: Compounds containing the -SH radical.Detergents: Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.Aspergillus niger: An imperfect fungus causing smut or black mold of several fruits, vegetables, etc.Isoflurophate: A di-isopropyl-fluorophosphate which is an irreversible cholinesterase inhibitor used to investigate the NERVOUS SYSTEM.Deoxyribonucleases: Enzymes which catalyze the hydrolases of ester bonds within DNA. EC 3.1.-.Radioimmunoassay: Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.Cellulase: An endocellulase with specificity for the hydrolysis of 1,4-beta-glucosidic linkages in CELLULOSE, lichenin, and cereal beta-glucans.Papain: A proteolytic enzyme obtained from Carica papaya. It is also the name used for a purified mixture of papain and CHYMOPAPAIN that is used as a topical enzymatic debriding agent. EC 3.4.22.2.Culture Media: Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.Crotalid Venoms: Venoms from snakes of the subfamily Crotalinae or pit vipers, found mostly in the Americas. They include the rattlesnake, cottonmouth, fer-de-lance, bushmaster, and American copperhead. Their venoms contain nontoxic proteins, cardio-, hemo-, cyto-, and neurotoxins, and many enzymes, especially phospholipases A. Many of the toxins have been characterized.Organ Specificity: Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen.Profilins: A family of low molecular weight proteins that bind ACTIN and control actin polymerization. They are found in eukaryotes and are ubiquitously expressed.Lectins: Proteins that share the common characteristic of binding to carbohydrates. Some ANTIBODIES and carbohydrate-metabolizing proteins (ENZYMES) also bind to carbohydrates, however they are not considered lectins. PLANT LECTINS are carbohydrate-binding proteins that have been primarily identified by their hemagglutinating activity (HEMAGGLUTININS). However, a variety of lectins occur in animal species where they serve diverse array of functions through specific carbohydrate recognition.Mitosporic Fungi: A large and heterogenous group of fungi whose common characteristic is the absence of a sexual state. Many of the pathogenic fungi in humans belong to this group.ChymotrypsinogenGlutathione Transferase: A transferase that catalyzes the addition of aliphatic, aromatic, or heterocyclic FREE RADICALS as well as EPOXIDES and arene oxides to GLUTATHIONE. Addition takes place at the SULFUR. It also catalyzes the reduction of polyol nitrate by glutathione to polyol and nitrite.Tissue Extracts: Preparations made from animal tissues or organs (ANIMAL STRUCTURES). They usually contain many components, any one of which may be pharmacologically or physiologically active. Tissue extracts may contain specific, but uncharacterized factors or proteins with specific actions.Viral Proteins: Proteins found in any species of virus.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Polygalacturonase: A cell wall-degrading enzyme found in microorganisms and higher plants. It catalyzes the random hydrolysis of 1,4-alpha-D-galactosiduronic linkages in pectate and other galacturonans. EC 3.2.1.15.Alcaligenes: A genus of gram-negative, aerobic, motile bacteria that occur in water and soil. Some are common inhabitants of the intestinal tract of vertebrates. These bacteria occasionally cause opportunistic infections in humans.Agaricus: A basidiomycetous fungal genus of the family Agaricaceae, order Agaricales, which includes the field mushroom (A. campestris) and the commercial mushroom (A. bisporus).Cytochrome c Group: A group of cytochromes with covalent thioether linkages between either or both of the vinyl side chains of protoheme and the protein. (Enzyme Nomenclature, 1992, p539)Protein Biosynthesis: The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.Surface Properties: Characteristics or attributes of the outer boundaries of objects, including molecules.Proteomics: The systematic study of the complete complement of proteins (PROTEOME) of organisms.Cathepsin H: An ubiquitously-expressed lysosomal cysteine protease that is involved in protein processing. The enzyme has both endopeptidase and aminopeptidase activities.Flavobacterium: A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in SOIL and WATER. Its organisms are also found in raw meats, MILK and other FOOD, hospital environments, and human clinical specimens. Some species are pathogenic in humans.Trichoderma: A mitosporic fungal genus frequently found in soil and on wood. It is sometimes used for controlling pathogenic fungi. Its teleomorph is HYPOCREA.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.

Purification and properties of a low-molecular-weight, high-alkaline pectate lyase from an alkaliphilic strain of Bacillus. (1/2317)

A low-molecular-weight, high-alkaline pectate lyase (pectate transeliminase, EC 4.2.2.2) was found in an alkaline culture of Bacillus sp. strain KSM-P15, purified to homogeneity, and crystallized. The enzyme had a relative molecular weight of approximately 20,300 as measured by sedimentation equilibrium, with a sedimentation coefficient (s20,w0) of 1.73 S. It was a basic protein with an isoelectric point of pH 10.3, and the alpha-helical content was only 6.6%. In the presence of Ca2+ ions, the enzyme degraded polygalacturonic acid in a random manner to yield 4,5-unsaturated oligo-galacturonides and had its optimal activity around pH 10.5 and 50-55 degrees C. It also had a protopectinase-like activity on cotton fibers. The N-terminal amino acid sequences of the intact protein (28 amino acids) and its two lysyl endopeptidase-cleaved peptide fragments (8 and 12 amino acids) had very low sequence similarity with pectate lyases reported to date. These results strongly suggest that the pectate lyase of Bacillus sp. strain KSM-P15 may be a novel enzyme and belongs in a new family.  (+info)

Prophenoloxidase-activating enzyme of the silkworm, Bombyx mori. Purification, characterization, and cDNA cloning. (2/2317)

Prophenoloxidase-activating enzyme (PPAE) was purified to homogeneity as judged by SDS-polyacrylamide gel electrophoresis from larval cuticles of the silkworm, Bombyx mori. The purified PPAE preparation was shown to be a mixture of the isozymes of PPAE (PPAE-I and PPAE-II), which were eluted at different retention times in reversed-phase high performance liquid chromatography. PPAE-I and PPAE-II seemed to be post translationally modified isozymes and/or allelic variants. Both PPAE isozymes were proteins composed of two polypeptides (heavy and light chains) that are linked by disulfide linkage(s) and glycosylated serine proteases. The results of cDNA cloning, peptide mapping, and amino acid sequencing of PPAE revealed that PPAE is synthesized as prepro-PPAE with 441 amino acid residues and is activated from pro-PPAE by cleavage of a peptide bond between Lys152 and Ile153. The homology search showed 36.9% identity of PPAE to easter, which is a serine protease involved in dorso-ventral pattern formation in the Drosophila embryo, and indicated the presence of two consecutive clip-like domains in the light chain. A single copy of the PPAE gene was suggested to be present in the silkworm genome. In the fifth instar larvae, PPAE transcripts were detected in the integument, hemocytes, and salivary glands but not in the fat body or mid gut. A polypeptide cross-reactive to mono-specific anti-PPAE/IgG was transiently detected in the extract of eggs between 1 and 3 h after they were laid.  (+info)

The relationship of glycosylation and isoelectric point with tumor accumulation of avidin. (3/2317)

Radiolabeled avidin markedly accumulated in intraperitoneal tumors and was cleared rapidly from circulation when given intraperitoneally. This study investigated the mechanisms of the tumor localization of avidin. METHODS: Avidin was deglycosylated through endoglycosydase-H digestion and/or neutralized by acetylation of its lysine amino acids with acetic acid N-hydroxysuccinimide ester. Avidin and modified avidins were analyzed using sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS/PAGE) and isoelectric focusing. A tumor model was established by intraperitoneal injection of human colon cancer cells, LS180, in nude mice. Avidin and modified avidins were labeled with 111In using diethyleneamine pentaacetic acid-biotin and were administered intraperitoneally into the tumor-bearing mice. The biodistribution of radioactivity was examined 2 and 24 h postinjection. RESULTS: Deglycosylated avidins revealed a major band of smaller molecules on SDS/PAGE. The isoelectric point of neutralized avidins was reduced to less than 5, whereas that of unneutralized avidins was more than 9.5. Biodistribution study demonstrated that liver uptake was decreased by deglycosylation and kidney accumulation was decreased by neutralization, respectively. The blood clearance was remarkably slowed by combined modification of deglycosylation and neutralization. The tumor uptake of radioactivity was reduced by either deglycosylation or neutralization and was further decreased with combined modification. CONCLUSION: Both high glycosylation and positive charge of avidin contributed to its accumulation in tumor. This study may facilitate development of a new vehicle for the delivery of therapeutic agents to intraperitoneal tumors.  (+info)

The purification and characterization of rabbit placental lactogen. (4/2317)

Rabbit placental lactogen, a polypeptide hormone functionally related to the growth hormone/prolactin family, was isolated from placenta by (NH4)2SO4 precipitation, gel filtration and ion-exchange chromatography on DEAE-and CM-cellulose. The hormone was purified to more than 90% homogeneity, as determined by end-group analysis. On disc gel electrophoresis at pH9.0 it migrates as a pair of closely spaced bands with mobilities of 0.489 (minor band) and 0.511 (major band), and its isoelectric point is 6.1. Its mol.wt. is 20600, as determined by sedimentation--equilibrium centrifugation, and 24200, as estimated by gel electrophoresis in sodium dodecyl sulphate. Its amino acid composition resembles that of rabbit growth hormone and rat prolactin, except for a lower glutamic acid and leucine content. Like the prolactins, rabbit placental lactogen has two tryptophan and six cysteine residues, and its N-terminus, valine, is identical with that for human placental lactogen. By radioimmunoassay, it does not cross-react with antisera to either rat growth hormone or rat prolactin; in addition, it does not cross-react with antisera to bovine placental lactogen by double immunodiffusion. The similarity of the biochemical characteristics of rabbit placental lactogen to the other non-primate placental lactogens lends further support to the hypothesis that these molecules occupy a more central position in the growth hormone/prolactin "tree" than do their primate counterparts.  (+info)

Identification of the reactive cysteine residue (Cys227) in human carbonyl reductase. (5/2317)

Carbonyl reductase is highly susceptible to inactivation by organomercurials suggesting the presence of a reactive cysteine residue in, or close to, the active site. This residue is also close to a site which binds glutathione. Structurally, carbonyl reductase belongs to the short-chain dehydrogenase/reductase family and contains five cysteine residues, none of which is conserved within the family. In order to identify the reactive residue and investigate its possible role in glutathione binding, alanine was substituted for each cysteine residue of human carbonyl reductase by site-directed mutagenesis. The mutant enzymes were expressed in Escherichia coli and purified to homogeneity. Four of the five mutants (C26A, C122A C150A and C226A) exhibited wild-type-like enzyme activity, although K(m) values of C226A for three structurally different substrates were increased threefold to 10-fold. The fifth mutant, C227A, showed a 10-15-fold decrease in kcat and a threefold to 40-fold increase in K(m), resulting in a 30-500-fold drop in kcat/K(m). NaCl (300 mM) increased the activity of C227A 16-fold, whereas the activity of the wild-type enzyme was only doubled. Substitution of serine rather than alanine for Cys227 similarly affected the kinetic constants with the exception that NaCl did not activate the enzyme. Both C227A and C227S mutants were insensitive to inactivation by 4-hydroxymercuribenzoate. Unlike the parent carbonyl compounds, the glutathione adducts of menadione and prostaglandin A1 were better substrates for the C227A and C227S mutants than the wild-type enzyme. Conversely, the binding of free glutathione to both mutants was reduced. Our findings indicate that Cys227 is the reactive residue and suggest that it is involved in the binding of both substrate and glutathione.  (+info)

Rapid purification of membrane extrinsic F1-domain of chloroplast ATP synthase in monodisperse form suitable for 3D-crystallization. (6/2317)

A new chromatographic procedure for purification of the membrane extrinsic F1-domain of chloroplast ATP synthase is presented. The purification is achieved by a single anion exchange chromatography step. Determination of the enzyme-bound nucleotides reveals only 1 mole of ADP per complex. The purified enzyme shows a latent Ca(2+)-dependent ATPase activity of 1.0 mumol.mg-1 min-1 and a Mg(2+)-dependent activity of 4.4 mumol.mg-1 .min-1. Both activities are increased up to 8-10-fold after dithiothreitol activation. Analysis of the purified F1-complex by SDS/PAGE, silver staining and immunoblotting revealed that the preparation is uncontaminated by fragmented subunits or ribulose-1,5-bisphosphate carboxylase/oxygenase. Gel filtration experiments indicate that the preparation is homogenous and monodisperse. In order to determine the solubility minimum of the purified F1-complex the isoelectric point of the preparation was calculated from pH mapping on ion exchange columns. In agreement with calculations based on the amino acid sequence, a slightly acidic pI of 5.7 was found. Using ammonium sulphate as a precipitant the purified CF1-complex could be crystallized by MicroBatch.  (+info)

Alkali-treated collagen retained the triple helical conformation and the ligand activity for the cell adhesion via alpha2beta1 integrin. (7/2317)

Alkaline treatment is a good method for extracting collagen with high recovery even from an aged animal specimen. However, the properties of collagen treated under alkaline conditions have not been well established yet. By the treatment with a solution of 3% sodium hydroxide and 1.9% monomethylamine, the isoelectric point of type I collagen was lowered from 9.3 to 4.8 because of the conversions of Asn and Gln to Asp and Glu. With the acidification of the pI, the denaturation temperature of the collagen was decreased from 42 to 35 degrees C after 20 d treatment, but the collagen-specific triple helical conformation was maintained. Human keratinocytes and fibroblasts adhered to the alkali-treated collagen via the collagen receptor integrin alpha2beta1. This indicates that the alkali-treated collagen maintained its property as a biological adherent molecule. Unlike acid-soluble collagen, alkali-treated collagen lost the ability to form fibrils at neutral pH under physiological conditions. This ability was lost even after 4 h of alkaline treatment, when the denaturation temperature of the collagen did not change. On the other hand, the alkali-treated collagen formed a fibrous precipitate with a uniform diameter of 50-70 nm under acidic conditions at 30 degrees C.  (+info)

Calcium-binding protein S100A7 and epidermal-type fatty acid-binding protein are associated in the cytosol of human keratinocytes. (8/2317)

Expression of epidermal-type fatty acid-binding protein (E-FABP) and S100A7 has previously been shown to be elevated in psoriatic skin, a disease characterized by abnormal keratinocyte differentiation. However, no causal relationship between the up-regulation of these proteins and the disease has been shown. E-FABP is thought to be involved in cytosolic fatty acid (FA) transport, whereas the role of S100A7 is still unknown. In this report, we show by overlay assays that E-FABP, immobilized on nitrocellulose, is able to capture S100A7 from cytosolic psoriatic protein extracts and vice versa, suggesting the formation of a complex between the two proteins. Using purified E-FABP and S100A7, the complex can be reconstituted only in presence of EDTA. Moreover, we show that increased EDTA concentrations in psoriatic cytosolic protein extracts enhance complex formation. Partial complex disruption was obtained by the addition of physiological concentrations of Zn2+ (0.1 mM), whereas Ca2+ at 5 mM and Mg2+ at 30 mM had no effect. On the other hand, high Ca2+ concentrations (30 mM) resulted in partial complex disruption. Oleic acid-binding properties were observed for free E-FABP and the complex E-FABP-S100A7, but not for free S100A7. By using confocal microscopy we show that S100A7 and E-FABP are co-localized in the cytoplasm of differentiating keratinocytes from lesional psoriatic skin. These data indicate that formation of the E-FABP-S100A7 complex and its FA-binding function might be regulated at least by bivalent cations.  (+info)

  • Structural organization and functional divergence of high isoelectric point α-amylase genes in bread wheat ( Triticum aestivum L.) and barley ( Hordeum vulgare L. (biomedcentral.com)
  • High isoelectric point α-amylase genes ( Amy1 ) play major roles during cereal seed germination, and are associated with unacceptable high residual α-amylase activities in ripe wheat grains. (biomedcentral.com)
  • PIR supports the isoelectric point prediction based on Iterative method by choose the current pK set available from literature. (blogspot.ca)
  • pIvalues method values 1 solomon 3.4161 2 rodwell 3.3749 3 emboss 3.5322 4 lehninger 3.3711 5 grimsley 3.3012 6 patrickios 3.4220 7 DtaSelect 3.7848 8 toseland 3.3571 9 thurlkill 3.4784 10 nozaki_tanford 3.6445 ------------------------------- Scaling-up the isoelectric point prediction The first idea with pIR was to benchmark the state-of-art isoelectric point prediction algorithms and compare its performance. (blogspot.ca)
  • Dispersion graphs of outliers (green) and non-outliers (red) peptides on the Branca dataset using different isoelectric point prediction algorithms. (blogspot.ca)
  • Estimating the pH of the net neutral charge (isoelectric point) on a virus particle can allow basic prediction of how a given virus will interact with charged particles and surfaces in the environment. (asm.org)
  • All the Ags that exhibit numerous neutral/acidic isoelectric variants were immunochemically demonstrated to be deiminated proteins. (jimmunol.org)
  • In the case of the 14 C labelled NEM adduct the label was found to be spread amongst numerous protein components within the gel however, in the case of the 35 S labelled DTNB adducts, only a small proportion of the label was found in the protein material which was retained in the acidic isoelectric point (pI) region of the gel. (scirp.org)
  • pI 4.049737 ---------------------------------------------------------------------------------------- Most of the tools allow to compute the isoelectric point (example above) to individual sequences. (blogspot.ca)
  • The isoelectric point (pI) refers to the solution acidity value at which the peptide molecule has the net charge of zero. (sciencing.com)
  • Heffron and Mayer ( e01674-20 ) demonstrated improved isoelectric point calculation for a diverse set of viruses by excluding regions of basic residues on the capsid interior that electrostatically bind the genome (polynucleotide-binding regions), as determined either empirically or through modeling. (asm.org)
  • The isoelectric point (pI, pH(I), IEP), is the pH at which a particular molecule carries no net electrical charge in the statistical mean. (wikipedia.org)
  • The isoelectric point ( pI ), sometimes abbreviated to IEP , is the pH at which a particular molecule or surface carries no net electrical charge . (princeton.edu)
  • The isoelectric point is significant because it represents the pH at which the surface of each particle has zero electrical charge, and, thereby, interactions of the individual particles with the resins of the paint system can be controlled. (google.com)
  • The isoelectric point, or pI, is the pH at which a protein has zero net charge . (proteopedia.org)
  • When the pH is higher than the isoelectric point, the protein has negative charge, and when lower, positive charge. (proteopedia.org)
  • The isoelectric point (pI)/point of zero charge (pzc) of graphene plays a key role in a number of physico-chemical phenomena occurring at the graphene-liquid interface. (nih.gov)
  • At the pH below the actual isoelectric point, proteins hold the net positive charge, as well as above the Isoelectric Level protein carries a net negative charge. (ebioworld.com)
  • Recall that you can use isoelectric point (PI) to predict an amino acid's charge at any given pH. (mcatquestionoftheday.com)
  • iep can plot the ionization curve with respect to pH and write an output file of the data, where for each pH point the number of bound electrons and charge is given. (omictools.com)
  • Knowing how to find both charge and isoelectric point for amino acids is a critical MCAT skill. (leah4sci.com)
  • The word isoelectric or isoelectronic comes from 'iso,' which means the same, and 'electric,' which implies charge. (leah4sci.com)
  • We wished to investigate if the shifts in these requirements have resulted in marked changes in the isoelectric point and charge of milk proteins during evolution. (biomedcentral.com)
  • The isoelectric point ( pI ) and charge of a protein is important for solubility, subcellular localization, and interaction. (biomedcentral.com)
  • begingroup$ I still don't know why 7 amino acids are used for isoelectric point and only 5 for net charge? (stackexchange.com)
  • Major differences in physicochemical and biochemical properties (i.e., sensitivity to Ca 2+ , stability at low pH and under heat treatment, and charge and serological characteristics) could be used to distinguish the two isoforms, which were eventually classified as high-pI and low-pI isoforms on the basis of isoelectric point (pI). (biomedcentral.com)
  • An electroconductive powder composition of antimony-containing tin oxide with an outer layer of hydrous metal oxide having an isoelectric point in the range from about 5 to 9. (google.com)
  • A good correlation between the isoelectric point values of insulin and its derivatives and their fusion properties was found. (biochemj.org)
  • The isoelectric point (pI) of a protein is of practical importance in many separation procedures, both analytical and preparative. (nus.edu.sg)
  • Second, go to the EMBL WWW Gateway to Isoelectric Point Service , paste your sequence in the box, and press the button. (proteopedia.org)
  • The white profile superimposed on the 2D-map indicates the position of the Dirac point estimated from the profiles such as in (b). (b) Line profiles extracted from the 2D-map showing the gate dependence of graphene resistance in four different solutions, where the shift in Dirac point is discernible. (nih.gov)
  • Practice: Estimate the isoelectric point of the following dipeptide in the figure. (clutchprep.com)
  • The isoelectric point is of significance in protein purification because it is the pH at which solubility is often minimal, and at which mobility in an electrofocusing system is zero (and therefore the point at which the protein will accumulate). (academic.ru)
  • In particular, this invention relates to compositions containing enzymes which have been modified to exhibit a low isoelectric point and methods for cleaning human-worn contact lenses with those compositions. (google.com)
  • However, to predict the isoelectric point of a list of peptides/proteins (for example, a short list of sequences contained in a file) the following option could be used: ---------------------------------------------------------------------------------------- #reading sequences from any file >peptides colnames (peptides) (blogspot.ca)
  • The chemical composition of the mitochondrial outer membrane is one of the factors defining the mitochondrial isoelectric point (pI), which is a property useful for the analysis and characterization of isolated mitochondria. (biomedsearch.com)
  • absorbent point in root canal therapy , a cone of variable width and taper, usually made of paper or a paper product, used to dry or maintain a liquid disinfectant in the canal. (thefreedictionary.com)