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42-422: Coomassie may refer to: Coomassie brilliant blue , a dye Coomassie, an historical name for Kumasi , Ghana, and namesake of the dye See also [ edit ] Ibrahim Coomassie , Nigerian police officer Abidina Coomassie , Nigerian journalist Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

84-401: A cellulose acetate sheet. The sheet was then soaked in sulfosalicylic acid to fix the protein bands and transferred to a solution of the dye. Two years later in 1965 Meyer and Lambert used Coomassie brilliant blue R-250 to stain protein samples after electrophoretic separation in a polyacrylamide gel . They soaked the gel in a dye solution containing methanol , acetic acid and water. As

126-426: A brownish colour but on binding to the protein the blue form of the dye is produced. The optical absorbance of the solution is measured at a wavelength of 595 nm. The dye is noted for its high level of sensitivity: 5 μg of protein can be detected. However, among the disadvantages of the method is its variability of color development with different proteins: the absorbance change per unit mass of proteins varies with

168-613: A draft risk assessment , and to provide the EC within 6 months with a conclusion. The assessment, received by the EFSA in 2007 started the peer review in October 2007 by dispatching it for consultation of the EC member states and the applicants, the two manufacturers, Cerexagri s.a., Italian subsidiary of United Phosphorus Ltd (UPL), and Pace International LLC. As a result of the peer review, mostly lacking data about risk to consumers, and particularly

210-440: A pH of around zero the dye will be a cation with an overall charge of +1. The green colour corresponds to a form of the dye with no net overall charge. In neutral media (pH 7), only the nitrogen atom of the diphenylamine moiety carries a positive charge and the blue dye molecule is an anion with an overall charge of −1. The p K a values for the losses of the two protons are 1.15 and 1.82, respectively. The final proton

252-434: A patient to reach the emergency room, the treatment needs to be effective even when administered up to two hours after injury. The only reported side effect was that the rats temporarily turned blue. Under the trade names ILM Blue and Brilliant Peel, brilliant blue G is used as a stain to assist surgeons in retinal surgery. In December 2019, brilliant blue G (under the trade name TissueBlue, DORC International, Netherlands)

294-458: A possible mutagenic or teratogenic effect. No effect on development could be attributed. The U.S. CDC's NIOSH lists the following symptoms of poisoning: irritation eyes, skin, mucous membrane; eczema; tachycardia, hypertension; cough, sneezing; methemoglobinemia; increased blood pressure and heart rate; proteinuria, hematuria (blood in the urine), bladder injury; in animals: teratogenic effects. The short-term NOAEL of 9.6 – 10 mg/kg bw/day

336-537: A white or yellowish powder with m.p. 123-125 °C. Diphenylamine undergoes various cyclisation reactions. With sulfur , it gives phenothiazine , a precursor to pharmaceuticals. With iodine, it undergoes dehydrogenation to give carbazole , with release of hydrogen iodide : Arylation with iodobenzene gives triphenylamine . it is also used as a test reagent in the dische's test . The Dische test uses diphenylamine to test for DNA , and can be used to distinguish DNA from RNA. Diphenylamine

378-442: Is a data gap on presence or formation of nitrosamines in apple metabolism or during processing. The carcinogen 4-Aminobiphenyl can accompany diphenylamine as an impurity. Diphenylamine has low acute and short-term toxicity to birds, but is very toxic to aquatic organisms. Risk to biological methods of sewage treatment was assessed as low. The impurity in commercial diphenylamine which induces polycystic kidney disease in rats

420-433: Is an organic compound with the formula (C 6 H 5 ) 2 NH. The compound is a derivative of aniline , consisting of an amine bound to two phenyl groups. The compound is a colorless solid, but commercial samples are often yellow due to oxidized impurities. Diphenylamine dissolves well in many common organic solvents, and is moderately soluble in water. It is used mainly for its antioxidant properties. Diphenylamine

462-457: Is commonly used as a stabilizer, such that the gunshot residue analysis seeks to quantify traces of diphenylamine. Diphenylamine functions by binding nitrogen oxide degradation products), forming compounds like nitrodiphenylamine . In this way, DPA prevents these degradation products from accelerating further degradation. Alkylated diphenylamines function as antioxidants in lubricants, approved for use in machines, in which contact with food

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504-440: Is lost under alkaline conditions and the dye becomes pink (p K a 12.4). The dye interacts electrostatically but noncovalently with the amino and carboxyl groups of proteins. The dye molecules bind to proteins, including those in wool ( keratin ), to form a protein–dye complex. The formation of the complex stabilises the negatively charged anionic form of the dye, producing the blue colour, even under acid conditions when most of

546-492: Is not ruled out. Alkylated diphenylamines and other derivatives are used as antiozonants in the manufacture of rubber products, reflecting the antioxidant nature of aniline derivatives. Many diphenylamine derivatives are used as redox indicators that are particularly useful in alkaline redox titrations. The diphenylaminesulfonic acid is a simple prototype redox indicator, owing to its improved aqueous solubility compared with diphenylamine. Attempts have been made to explain

588-425: Is used as a pre- or postharvest scald inhibitor for apples applied as an indoor drench treatment. Its anti-scald activity is the result of its antioxidant properties, which protect the apple skin from the oxidation products of α- farnesene during storage. Apple scald is physical injury that manifests in brown spots after fruit is removed from cold storage. In the manufacture of smokeless powder , diphenylamine

630-437: Is widely used as an industrial antioxidant , dye mordant and reagent and is also employed in agriculture as a fungicide and antihelmintic . Diphenylamine is manufactured by the thermal deamination of aniline over oxide catalysts : It is a weak base, with a K b of 10 . With strong acids, it forms salts. For example, treatment with sulfuric acid gives the bisulfate [(C 6 H 5 ) 2 NH 2 ] [HSO 4 ] as

672-527: The Colour Index lists over 40 dyes with "Coomassie" in their name. There are also other Coomassie "blue" dyes. For example, the Merck Index (10th edition) lists Coomassie Blue RL (Acid Blue 92, C.I. 13390), which has a completely different structure. The suffix "R" in the name of Coomassie brilliant blue R-250 is an abbreviation for "red" as the blue colour of the dye has a slight reddish tint. For

714-482: The biological sex of the fingerprint. Female samples were shown to have a higher absorbance than male samples when tested at similar wavelengths. This provides a simpler method for fingerprint analysis by reducing the number of amino acids needing to be analyzed from 23 to 6 and requires little to no assay preparation, in contrast to the ninhydrin chemical assay, which requires assay preparation such as heating and enzyme cascade. Diphenylamine Diphenylamine

756-441: The "G" variant the blue colour has a more greenish tint. The "250" originally denoted the purity of the dye. The colour of the two dyes depends on the acidity of the solution. The "G" form of the dye has been studied in detail. At a pH of less than 0 the dye has a red colour with an absorption maximum at a wavelength of 465 nm. At a pH of around 1 the dye is green with an absorption maximum at 620 nm while above pH 2

798-529: The Coomassie trademark, the company no longer manufactures the dyes. The blue disulfonated triphenylmethane dyes were first produced in 1913 by Max Weiler, who was based in Elberfeld , Germany. Various patents were subsequently taken out on the organic synthesis. Papers published in biochemistry journals frequently refer to these dyes simply as "Coomassie" without specifying which dye was used. In fact,

840-505: The EC with more data, and an additional report was received by the EFSA on 3 December 2010. EFSA concluded the risk assessment did not eliminate the concerns on 5 December 2011, published this opinion in 2012 and it became law in 2013. The committee established an acceptable daily intake of 0.02 mg/kg/day in a meeting on pesticide residues. After passage of the Food Quality Protection Act (FQPA) of 1996,

882-401: The G form of dye in a solution containing phosphoric acid, ethanol (or methanol) and ammonium sulfate (or aluminium sulfate ). The Bradford assay uses the spectral properties of Coomassie brilliant blue G-250 to estimate the amount of protein in a solution. A protein sample is added to a solution of the dye in phosphoric acid and ethanol. Under the acid conditions the dye is normally

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924-551: The anionic detergent sodium dodecylsulfate (SDS). The formation of this complex stabilizes the neutral, green form of the dye. This effect can interfere with the estimation of protein concentration using the Bradford assay. It is also likely that the anionic detergent competes with the dye for binding to the protein. Coomassie brilliant blue R-250 was first used to visualise proteins in 1963 by Fazekas de St. Groth and colleagues. Protein samples were separated electrophoretically on

966-422: The area to die of metabolic stress. Testing on the rats proved effective. In comparison to the rats that had not received the dye, the rats that were treated with the dye performed better on motion tests. It is unknown whether this treatment can be used effectively in humans. The animal experiments administered the dye within 15 minutes of injury, but to be effective in a real-life setting, where it may take time for

1008-451: The color changes associated with the oxidation of diphenylamine. In a related application, diphenylamine is oxidized by nitrate to give a similar blue coloration in the diphenylamine test for nitrates . Several azo dyes like Metanil Yellow , Disperse Orange 1 , and Acid orange 5 are derivatives of diphenylamine. It is also used as a dye mordant . A dye mordant is any substance that helps dyes to adhere to fabrics. Diphenylamine

1050-496: The control of scald of apples. The EC set maximum residue levels for diphenylamine in 2005. (Annex II and Part B of Annex III to Regulation (EC) No 396/2005). Diphenylamine was one of 84 substances of a European Commission (EC) review program covered by a regulation from 2002 requiring the European Food Safety Authority (EFSA) upon EC request to organize a peer review of the initial evaluation, i.e.

1092-401: The dye is bright blue with a maximum at 595 nm. At pH 7 the dye has an extinction coefficient of 43,000 M  cm . The different colours are a result of the different charged states of the dye molecule. In the red form, all three nitrogen atoms carry a positive charge. The two sulfonic acid groups have extremely low p K a and will normally be negatively charged, thus at

1134-417: The dye stained the polyacrylamide gel as well as the protein, in order to visualise the protein bands they needed to destain the gel, which they did electrophoretically. Subsequent publications reported that polyacrylamide gels could be successfully destained using an acetic acid solution. The first report of the use of the G form of the dye to visualise protein bands in polyacrylamide gels came in 1967, where

1176-399: The dye was dissolved in an acetic acid solution containing methanol. It was subsequently discovered that the protein bands could be stained without staining the polyacrylamide by using a colloid of the G form of the dye in a trichloroacetic acid solution containing no methanol. With this procedure it was no longer necessary to destain the gel. Modern formulations typically use a colloid of

1218-565: The eyes. It was not a skin irritant, and it has not been technically feasible to test acute toxicity study by inhalation. Diphenylamine targets the red blood cell system and can cause abnormal erythropoiesis in the spleen, and thus congestion of the spleen, and haemosiderosis . Changes in liver and kidneys were found upon longer exposure. At clear toxic doses of parent animals reproductive effects were limited to reduced implantation sites in F1 females associated with reduced rat litter size, implicating

1260-499: The levels and toxicity of unidentified metabolites of the substance, the possible formation of nitrosamines during storage of the active substance and during processing of treated apples, and the lack of data on the potential breakdown product of diphenylamine residues in processed commodities, the EC decided on 30 November 2009 to withdraw authorizations for plant protection products containing diphenylamine.(2009/859/EC) The 'European Diphenylamine Task Force' resubmitted an application to

1302-458: The molecules in solution are in the cationic form. This is the basis of the Bradford assay , which quantifies protein by Coomassie brilliant blue dye binding. The binding of the dye to a protein causes a shift in the absorbance maximum of the dye from 465 to 595 nm. The increase of absorption at 595 nm is monitored to determine protein concentration. The dye also forms a complex with

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1344-458: The size of the protein complex (i.e., the molecular weight) and the amount of dye bound to the protein. Coomassie blue staining can also be used as a loading control staining method in western blot analysis. It is applied as an anionic pre-antibody stain. In 2009, brilliant blue G was used in scientific experiments to treat spinal injuries in laboratory rats. It acts by reducing the body's natural swelling response, which can cause neurons in

1386-480: The title Coomassie . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Coomassie&oldid=1072673060 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Coomassie brilliant blue The name Coomassie

1428-431: The type of the protein. On binding to a protein, the negatively charged Coomassie brilliant blue G-250 dye molecule will give an overall negative charge to the protein. This property can be used to separate proteins or protein complexes using polyacrylamide gel electrophoresis under non-denaturing conditions in a technique called blue native PAGE . The mobility of the complex in the polyacrylamide gel will depend on both

1470-654: 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

1512-532: Was also being used to detect nitrites and nitrates in drinking water. In 1924, diphenylamine is discovered to be useful in detecting DNA via the Dische test by Zacharias Dische . In animal experiments diphenylamine was rapidly and completely absorbed after ingestion by mouth. It underwent metabolism to sulfonyl and glucuronyl conjugates and was rapidly excreted mainly via urine. Acute oral and dermal toxicity were low. Diphenylamine can cause severe irritation to

1554-592: Was approved for use in humans in the United States. Tissueblue was approved for medical use in Canada in January 2021. The ability of the Coomassie dye to target amino acids with aromatic groups ( phenylalanine , tyrosine , tryptophan ) and basic side chains ( lysine , arginine and histidine ) allows the Bradford assay to be used for fingerprint analysis. The assay was successfully used to identify

1596-513: Was derived from 90-day rat, 90-day dog and 1-year dog studies and the long-term NOAEL was 7.5 mg/kg bw/day. The Acceptable Daily Intake of diphenylamine was 0.075 mg/kg bw/day based on the 2-year rat study, applying a safety factor of 100; the Acceptable Operator Exposure Level was 0.1 mg/kg bw/day. In a study of diphenylamine metabolism in harvested and dipped apples at different time intervals it

1638-413: Was discovered by A. W. Hofmann in 1864 amongst the products of dry distillation of aniline dyes; it was first purposefully synthesized through deamination of a mix of aniline and its salts by a group of French chemists two years later. In 1872, diphenylamine was suggested as a means to detect nitrous acid in sulfuric acid due to its blue coloration in the presence of oxidizing agents . By 1875, it

1680-402: Was estimated. Despite limited data, the information was sufficient for the EC to characterize the environmental risk as negligible, because the intended use of diphenylamine was indoors. Of 744 apples tested USDA found 82.7% of them to have diphenylamine residue between 0.005 - 4.3 ppm, below the U.S. EPA's tolerance level of 10ppm. A number of alternatives to the use of diphenylamine exist for

1722-429: Was identified in 1981. Laboratory studies with highly purified diphenylamine indicated that the impurity can be formed by heating diphenylamine. Diphenylamine is considered practically insoluble according to the 2014 MSDS. It exhibits very low persistence in direct water photolysis experiments in the laboratory and is moderately volatile. Indirect photooxidation in the atmosphere through reaction with hydroxyl radicals

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1764-566: Was observed that radiolabelled residues of diphenylamine penetrate from the surface into the pulp, which after 40 weeks contained 32% of the residue. Diphenylamine was always the major residue, but 3 metabolites were found in good amounts in the apple samples, whose identification experts considered insufficient.(Kim-Kang, H. 1993. Metabolism of 14C-diphenylamine in stored apples—nature of the residue in plants. Report RPT00124. Study XBL 91071. XenoBiotic Laboratories, Inc., USA, unpublished) cited in There

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