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Nitrogen Solubility Index
The nitrogen solubility index (NSI) is a measure of the solubility of the protein in a substance. It is typically used as a quick measure of the functionality of a protein, for example to predict the ability of the protein to stabilise foams, emulsions or gels. To determine the NSI, the sample is dried, dispersed in a 0.1 M salt solution, centrifuged and filtered. The NSI is the amount of Nitrogen in this filtered solution divided by the nitrogen in the initial sample, as measured by the Kjeldahl method The Kjeldahl method or Kjeldahl digestion () in analytical chemistry is a method for the quantitative determination of a sample's organic compound, organic nitrogen plus ammonia/ammonium (NH3/NH4+). Without modification, other forms of inorganic ni .... The relevance of the NSI is based on the fact that proteins are the major biological source of Nitrogen: for various types of protein, there are empirical formulas which correlate the nitrogen content to the protein content. Other re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solubility
In chemistry, solubility is the ability of a chemical substance, substance, the solute, to form a solution (chemistry), solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubility of a substance in a specific solvent is generally measured as the concentration of the solute in a wikt:saturated#Chemistry, saturated solution, one in which no more solute can be dissolved. At this point, the two substances are said to be at the solubility equilibrium. For some solutes and solvents, there may be no such limit, in which case the two substances are said to be "miscibility, miscible in all proportions" (or just "miscible"). The solute can be a solid, a liquid, or a gas, while the solvent is usually solid or liquid. Both may be pure substances, or may themselves be solutions. Gases are always miscible in all proportions, except in very extreme situations,J. de Swaan Arons and G. A. ... [...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 residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 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 pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molar Concentration
Molar concentration (also called molarity, amount concentration or substance concentration) is the number of moles of solute per liter of solution. Specifically, It is a measure of the concentration of a chemical species, in particular, of a solute in a solution, in terms of amount of substance per unit volume of solution. In chemistry, the most commonly used unit for molarity is the number of moles per liter, having the unit symbol mol/L or mol/ dm3 (1000 mol/ m3) in SI units. A solution with a concentration of 1 mol/L is said to be 1 molar, commonly designated as 1 M or 1 M. Molarity is often depicted with square brackets around the substance of interest; for example, the molarity of the hydrogen ion is depicted as + Definition Molar concentration or molarity is most commonly expressed in units of moles of solute per litre of solution. For use in broader applications, it is defined as amount of substance of solute per unit volume of solution, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kjeldahl Method
The Kjeldahl method or Kjeldahl digestion () in analytical chemistry is a method for the quantitative determination of a sample's organic compound, organic nitrogen plus ammonia/ammonium (NH3/NH4+). Without modification, other forms of inorganic nitrogen, for instance nitrate, are not included in this measurement. Using an empirical relation between Kjeldahl nitrogen and protein, it is an important method for indirectly quantifying protein content of a sample. This method was developed by the Denmark, Danish chemist Johan Kjeldahl in 1883.Kjeldahl, J. (1883)"Neue Methode zur Bestimmung des Stickstoffs in organischen Körpern"(New method for the determination of nitrogen in organic substances), ''Zeitschrift für analytische Chemie'', 22 (1) : 366–383. Method The method consists of heating a sample to 360–410 °C with concentrated sulfuric acid (), which decomposes, or digests, the organic sample by Redox, oxidation to liberate the reduced nitrogen as stable ammonium sulfate: . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
