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Protein Methods
Protein methods are the techniques used to study proteins. There are experimental methods for studying proteins (e.g., for detecting proteins, for isolating and purifying proteins, and for characterizing the structure and function of proteins, often requiring that the protein first be purified). Computational methods typically use computer programs to analyze proteins. However, many experimental methods (e.g., mass spectrometry) require computational analysis of the raw data. Genetic methods Experimental analysis of proteins typically requires expression and purification of proteins. Expression is achieved by manipulating DNA that encodes the protein(s) of interest. Hence, protein analysis usually requires DNA methods, especially cloning. Some examples of genetic methods include conceptual translation, Site-directed mutagenesis, using a fusion protein, and matching allele with disease states. Some proteins have never been directly sequenced, however by translating codons from know ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gel Electrophoresis
Gel electrophoresis is a method for separation and analysis of biomacromolecules ( DNA, RNA, proteins, etc.) and their fragments, based on their size and charge. It is used in clinical chemistry to separate proteins by charge or size (IEF agarose, essentially size independent) and in biochemistry and molecular biology to separate a mixed population of DNA and RNA fragments by length, to estimate the size of DNA and RNA fragments or to separate proteins by charge. Nucleic acid molecules are separated by applying an electric field to move the negatively charged molecules through a matrix of agarose or other substances. Shorter molecules move faster and migrate farther than longer ones because shorter molecules migrate more easily through the pores of the gel. This phenomenon is called sieving. Proteins are separated by the charge in agarose because the pores of the gel are too small to sieve proteins. Gel electrophoresis can also be used for the separation of nanoparticles. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amido Black 10B
Amido black 10B is an amino acid staining azo dye used in biochemical research to stain for total protein on transferred membrane blots, such as the western blot. It is also used in criminal investigations to detect blood present with latent fingerprints. It stains the proteins in blood a blue-black color. Amido Black can be either methanol or water based as it readily dissolves in both. With picric acid, in a van Gieson procedure, it can be used to stain collagen and reticulin. See also *Western blot normalization Normalization of Western blot data is an analytical step that is performed to compare the relative abundance of a specific protein across the lanes of a blot or gel under diverse experimental treatments, or across tissues or developmental stages. T ... References External linksMSDS at Oxford University {{DEFAULTSORT:Amido Black 10b Azo dyes Naphthalenesulfonates Organic sodium salts 1-Naphthols Nitrobenzenes Aromatic amines Acid dyes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorescamine
Fluorescamine is a spiro compound that is not fluorescent itself, but reacts with primary amines to form highly fluorescent products. It hence has been used as a reagent for the detection of amines and peptides. 1-100 µg of protein and down 10 pg protein can be detected. by This method is found to suffer of high blanks resulting of high rate of hydrolysis due to used excess concentration. Alternative methods are based on ortho-Phthalaldehyde (OPA), Ellman's reagent (DTNB) and |
Lowry Protein Assay
The Lowry protein assay is a biochemical assay for determining the total level of protein in a solution. The total protein concentration is exhibited by a color change of the sample solution in proportion to protein concentration, which can then be measured using colorimetric techniques. It is named for the biochemist Oliver H. Lowry who developed the reagent in the 1940s. His 1951 paper describing the technique is the most-highly cited paper ever in the scientific literature, cited over 300,000 times. Mechanism The method combines the reactions of copper ions with the peptide bonds under alkaline conditions (the Biuret test) with the oxidation of aromatic protein residues. The Lowry method is based on the reaction of Cu+, produced by the oxidation of peptide bonds, with Folin–Ciocalteu reagent (a mixture of phosphotungstic acid and phosphomolybdic acid in the Folin–Ciocalteu reaction). The reaction mechanism is not well understood, but involves reduction of the Folin–Cioca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicinchoninic Acid Assay
The bicinchoninic acid assay (BCA assay), also known as the Smith assay, after its inventor, Paul K. Smith at the Pierce Chemical Company, now part of Thermo Fisher Scientific, is a biochemical assay for determining the total concentration of protein in a solution (0.5 μg/mL to 1.5 mg/mL), similar to Lowry protein assay, Bradford protein assay or biuret reagent. The total protein concentration is exhibited by a color change of the sample solution from green to purple in proportion to protein concentration, which can then be measured using colorimetric techniques. Mechanism A stock BCA solution contains the following ingredients in a highly alkaline solution with a pH 11.25: bicinchoninic acid, sodium carbonate, sodium bicarbonate, sodium tartrate, and copper(II) sulfate pentahydrate. The BCA assay primarily relies on two reactions. First, the peptide bonds in protein reduce Cu2+ ions from the copper(II) sulfate to Cu1+ (a temperature dependent reaction). The amount of Cu2+ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biuret Test
Biuret is a chemical compound with the chemical formula . It is a white solid that is soluble in hot water. A variety of organic derivatives are known. The term "biuret" also describes a family of organic compounds with the chemical formula , where are hydrogen, organyl or other groups. Also known as carbamylurea, it results from the condensation of two equivalents of urea. As such, it is an undesirable impurity in urea-based fertilizers. As biuret is toxic to plants, its percentage in fertilizers must be kept low. Preparation and structure The parent compound can be prepared by heating urea at 150 °C for ~6 hours until it gets slightly cloudy, then recrystallizing from water. After that, it can be recrystallized repeatedly from 2% sodium hydroxide solution and water to finally get base-free crystalline needles of the monohydrate which are free of cyanuric acid. While heating, a lot of ammonia is expelled: : Under related conditions, pyrolysis of urea affords triuret . In general ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bradford Protein Assay
The Bradford protein assay was developed by Marion M. Bradford in 1976. It is a quick and accurate spectroscopic analytical procedure used to measure the concentration of protein in a solution. The reaction is dependent on the amino acid composition of the measured proteins. Principle The Bradford assay, a colorimetric protein assay, is based on an absorbance shift of the dye Coomassie brilliant blue G-250. The Coomassie brilliant blue G-250 dye exists in three forms: anionic (blue), neutral (green), and cationic (red). Under acidic conditions, the red form of the dye is converted into its blue form, binding to the protein being assayed. If there's no protein to bind, then the solution will remain brown. The dye forms a strong, noncovalent complex with the protein's carboxyl group by van der Waals force and amino group through electrostatic interactions. During the formation of this complex, the red form of Coomassie dye first donates its free electron to the ionizable group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Detection
Protein detection is used for clinical diagnosis, treatment and biological research. Protein detection evaluates the concentration and amount of different proteins in a particular specimen. There are different methods and techniques to detect protein in different organisms. Protein detection has demonstrated important implications for clinical diagnosis, treatment and biological research. Protein detection technique has been utilized to discover protein in different category food, such as soybean (bean), walnut (nut), and beef (meat). Protein detection method for different type food vary on the basis of property of food for bean, nut and meat. Protein detection has different application in different field. Protein Detection in Soybeans, Walnuts, Beef Purpose for protein detection in food Allergies from food have been noted to become common disease nowadays. The food allergies in the clinical demonstration present different signs, for example mild symptoms from itching in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absorbance
Absorbance is defined as "the logarithm of the ratio of incident to transmitted radiant power through a sample (excluding the effects on cell walls)". Alternatively, for samples which scatter light, absorbance may be defined as "the negative logarithm of one minus absorptance, as measured on a uniform sample". The term is used in many technical areas to quantify the results of an experimental measurement. While the term has its origin in quantifying the absorption of light, it is often entangled with quantification of light which is “lost” to a detector system through other mechanisms. What these uses of the term tend to have in common is that they refer to a logarithm of the ratio of a quantity of light incident on a sample or material to that which is detected after the light has interacted with the sample. The term absorption refers to the physical process of absorbing light, while absorbance does not always measure only absorption; it may measure attenuation (of trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coomassie Brilliant Blue
Coomassie brilliant blue is the name of two similar triphenylmethane dyes that were developed for use in the textile industry but are now commonly used for staining proteins in analytical biochemistry. Coomassie brilliant blue G-250 differs from Coomassie brilliant blue R-250 by the addition of two methyl groups. The name "Coomassie" is a registered trademark of Imperial Chemical Industries. Name and discovery The name Coomassie was adopted at the end of the 19th century as a trade name by the Blackley-based dye manufacturer Levinstein Ltd, in marketing a range of acid wool dyes. In 1896 during the Fourth Anglo–Ashanti War, British forces had occupied the town of Coomassie (modern-day Kumasi in Ghana). In 1918 Levinstein Ltd became part of British Dyestuffs, which in 1926 became part of Imperial Chemical Industries. Although ICI still owns the Coomassie trademark, the company no longer manufactures the dyes. The blue disulfonated triphenylmethane dyes were first produced in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bradford Assay
The Bradford protein assay was developed by Marion M. Bradford in 1976. It is a quick and accurate spectroscopic analytical procedure used to measure the concentration of protein in a solution. The reaction is dependent on the amino acid composition of the measured proteins. Principle The Bradford assay, a colorimetric protein assay, is based on an absorbance shift of the dye Coomassie brilliant blue G-250. The Coomassie brilliant blue G-250 dye exists in three forms: anionic (blue), neutral (green), and cationic (red). Under acidic conditions, the red form of the dye is converted into its blue form, binding to the protein being assayed. If there's no protein to bind, then the solution will remain brown. The dye forms a strong, noncovalent complex with the protein's carboxyl group by van der Waals force and amino group through electrostatic interactions. During the formation of this complex, the red form of Coomassie dye first donates its free electron to the ionizable group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
