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Diethylpyrocarbonate
Diethyl pyrocarbonate (DEPC), also called diethyl dicarbonate (IUPAC name), is used in the laboratory to inactivate RNase enzymes in water and on laboratory utensils. It does so by the covalent modification of histidine (most strongly), lysine, cysteine, and tyrosine residues. DEPC-treated (and therefore RNase-free) water is used in handling of RNA in the laboratory to reduce the risk of RNA being degraded by RNases. Water is usually treated with 0.1% v/v DEPC for at least 2 hours at 37 °C and then autoclaved (at least 15 min) to inactivate traces of DEPC. Inactivation of DEPC in this manner yields CO2 and ethanol. Higher concentrations of DEPC are capable of deactivating larger amounts of RNase, but remaining traces or byproducts may inhibit further biochemical reactions such as in vitro transcription. Furthermore, chemical modification of RNA such as carboxymethylation is possible when traces of DEPC or its byproducts are present, resulting in impaired recovery of intact R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethyl Dicarbonate
Dimethyl dicarbonate (DMDC) is a colorless liquid and a pungent odor at high concentration at room temperature. It is primarily used as a beverage preservative, processing aid, or sterilant ( INS No. 242) being highly active against typical beverage spoiling microorganisms like yeast, bacteria, or mould. Usage Dimethyl dicarbonate is used to stabilize beverages by preventing microbial spoilage. It can be used in various non-alcoholic as well as alcoholic drinks like wine, cider, beer-mix beverages or hard seltzers. Beverage spoiling microbes are killed by methoxycarbonylation of proteins. It acts by inhibiting enzymes involved in the microbial metabolism, e.g. acetate kinase and L-glutamic acid decarboxylase. It has also been proposed that DMDC inhibits the enzymes alcohol dehydrogenase and glyceraldehyde 3-phosphate dehydrogenase by causing the methoxycarbonylation of their histidine components. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Di-tert-butyl Dicarbonate
Di-''tert''-butyl dicarbonate is a reagent widely used in organic synthesis. Since this compound can be regarded formally as the acid anhydride derived from a ''tert''-butoxycarbonyl (Boc) group, it is commonly referred to as Boc anhydride. This pyrocarbonate reacts with amines to give ''N''-''tert''-butoxycarbonyl or so-called Boc derivatives. These carbamate derivatives do not behave as amines, which allows certain subsequent transformations to occur that would be incompatible with the amine functional group. The Boc group can later be removed from the amine using moderately strong acids (e.g., trifluoroacetic acid). Thus, Boc serves as a protective group, for instance in solid phase peptide synthesis. Boc-protected amines are unreactive to most bases and nucleophiles, allowing for the use of the fluorenylmethyloxycarbonyl group (Fmoc) as an orthogonal protecting group. Preparation Di-''tert''-butyl dicarbonate is inexpensive, so it is usually purchased. Classically, this comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxylamine
Hydroxylamine is an inorganic compound with the formula . The material is a white crystalline, hygroscopic compound.Greenwood and Earnshaw. ''Chemistry of the Elements.'' 2nd Edition. Reed Educational and Professional Publishing Ltd. pp. 431–432. 1997. Hydroxylamine is almost always provided and used as an aqueous solution. It is consumed almost exclusively to produce Nylon-6. It is also an intermediate in biological nitrification. The oxidation of to hydroxylamine is a step in biological nitrification. History Hydroxylamine was first prepared as hydroxylammonium chloride in 1865 by the German chemist Wilhelm Clemens Lossen (1838-1906); he reacted tin and hydrochloric acid in the presence of ethyl nitrate. It was first prepared in pure form in 1891 by the Dutch chemist Lobry de Bruyn and by the French chemist Léon Maurice Crismer (1858-1944). The coordination complex , known as Crismer's salt, releases hydroxylamine upon heating. Production Hydroxylamine or its salts can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imidazole
Imidazole (ImH) is an organic compound with the formula C3N2H4. It is a white or colourless solid that is soluble in water, producing a mildly alkaline solution. In chemistry, it is an aromatic heterocycle, classified as a diazole Diazole refers to either one of a pair of isomeric chemical compounds with molecular formula C3H4N2, having a five-membered ring consisting of three carbon atoms and two nitrogen atoms. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Derivatization
Derivatization is a technique used in chemistry which converts a chemical compound into a product (the reaction's derivate) of similar chemical structure, called a derivative. Generally, a specific functional group of the compound participates in the derivatization reaction and transforms the educt to a derivate of deviating reactivity, solubility, boiling point, melting point, aggregate state, or chemical composition. Resulting new chemical properties can be used for quantification or separation of the educt. Derivatization techniques are frequently employed in chemical analysis of mixtures and in surface analysis, e.g. in X-ray photoelectron spectroscopy where newly incorporated atoms label characteristic groups. Derivatization reactions Several characteristics are desirable for a derivatization reaction: # The reaction is reliable and proceeds to completion. Less unreacted starting material will simplify analysis. Also, this allows a small amount of analyte to be used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MOPS
MOPS (3-(''N''-morpholino)propanesulfonic acid) is a buffer introduced in the 1960s, one of the twenty Good's buffers. It is a structural analog to MES, and like MES, its structure contains a morpholine ring. HEPES is a similar pH buffering compound that contains a piperazine ring. With a p''K''a of 7.20, MOPS is an excellent buffer for many biological systems at near-neutral pH. Applications MOPS is frequently used as a buffering agent in biology and biochemistry. It has been tested and recommended for polyacrylamide gel electrophoresis. Usage above 20 mM in mammalian cell culture work is not recommended. MOPS buffer solutions become discolored (yellow) over time, but reportedly slight discoloration does not significantly affect the buffering characteristics. See also *CAPS * HEPPS *Tris Tris, or tris(hydroxymethyl)aminomethane, or known during medical use as tromethamine or THAM, is an organic compound with the formula (HOCH2)3CNH2, one of the twenty Good's buffers. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphate-buffered Saline
Phosphate-buffered saline (PBS) is a buffer solution (pH ~ 7.4) commonly used in biological research. It is a water-based salt solution containing disodium hydrogen phosphate Disodium phosphate (DSP), or disodium hydrogen phosphate, or sodium phosphate dibasic, is the inorganic compound with the formula Na2HPO4. It is one of several sodium phosphates. The salt is known in anhydrous form as well as forms with 2, 7, 8, ..., sodium chloride and, in some formulations, potassium chloride and potassium dihydrogen phosphate. The buffer helps to maintain a constant pH. The osmolarity and ion concentrations of the solutions match those of the human body (tonicity, isotonic). Applications PBS has many uses because it is isotonic and non-toxic to most cells. These uses include substance dilution and cell container rinsing. PBS with EDTA is also used to disengage attached and clumped cells. Divalent metals such as zinc, however, cannot be added as this will result in precipitation. For the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HEPES
HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) is a zwitterionic sulfonic acid buffering agent; one of the twenty Good's buffers. HEPES is widely used in cell culture, largely because it is better at maintaining physiological pH despite changes in carbon dioxide concentration (produced by aerobic respiration) when compared to bicarbonate buffers, which are also commonly used in cell culture. Lepe-Zuniga ''et al.'' reported an unwanted photochemical process wherein HEPES when exposed to ambient light produces hydrogen peroxide, which is not a problem in bicarbonate-based cell culture buffers. It is therefore strongly advised to keep HEPES-containing solutions in darkness as much as possible to prevent oxidation. HEPES has the following characteristics: * p''K''a1 (25 °C) = 3 * p''K''a2 (25 °C) = 7.5 * Useful pH range = 2.5 to 3.5 or 6.8 to 8.2 HEPES has negligible metal ion binding, making it a good choice as a buffer for enzymes which might be inhibited ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tris
Tris, or tris(hydroxymethyl)aminomethane, or known during medical use as tromethamine or THAM, is an organic compound with the formula (HOCH2)3CNH2, one of the twenty Good's buffers. It is extensively used in biochemistry and molecular biology as a component of buffer solutions such as in TAE and TBE buffers, especially for solutions of nucleic acids. It contains a primary amine and thus undergoes the reactions associated with typical amines, e.g. condensations with aldehydes. Tris also complexes with metal ions in solution. In medicine, tromethamine is occasionally used as a drug, given in intensive care for its properties as a buffer for the treatment of severe metabolic acidosis in specific circumstances. Some medications are formulated as the "tromethamine salt" including Hemabate (carboprost as trometamol salt), and "ketorolac trometamol". Buffering features The conjugate acid of tris has a p''K''a of 8.07 at 25 °C, which implies that the buffer has an effective pH r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleophile
In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are Lewis bases. ''Nucleophilic'' describes the affinity of a nucleophile to bond with positively charged atomic nuclei. Nucleophilicity, sometimes referred to as nucleophile strength, refers to a substance's nucleophilic character and is often used to compare the affinity of atoms. Neutral nucleophilic reactions with solvents such as alcohols and water are named solvolysis. Nucleophiles may take part in nucleophilic substitution, whereby a nucleophile becomes attracted to a full or partial positive charge, and nucleophilic addition. Nucleophilicity is closely related to basicity. History The terms ''nucleophile'' and ''electrophile'' were introduced by Christopher Kelk Ingold in 1933, replacing the terms ''anionoid'' and ''cationoid' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autoclave
An autoclave is a machine used to carry out industrial and scientific processes requiring elevated temperature and pressure in relation to ambient pressure and/or temperature. Autoclaves are used before surgical procedures to perform sterilization and in the chemical industry to cure coatings and vulcanize rubber and for hydrothermal synthesis. Industrial autoclaves are used in industrial applications, especially in the manufacturing of composites. Many autoclaves are used to sterilize equipment and supplies by subjecting them to pressurized saturated steam at for around 30-60 minutes at a pressure of 15 psi (103 kPa or 1.02 atm) depending on the size of the load and the contents. The autoclave was invented by Charles Chamberland in 1879, although a precursor known as the steam digester was created by Denis Papin in 1679. The name comes from Greek ''auto-'', ultimately meaning self, and Latin ''clavis'' meaning key, thus a self-locking device. Uses Sterilization autoclav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
