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Topic: Biuret

	MINOR CONTAMINANTS OF BIURET AND CYANURIC ACID AS ADDITIVES FOR PEACH FRUIT THINNING WITH UREA
		Biuret and cyanuric acid (CA) are phytotoxic minor contaminants found in synthetic urea.
		The objective of the present study was to evaluate the contribution of biuret and CA to the fruit thinning effect of urea.
		A concentration of 160 ppm of biuret in 8% urea solution caused some synergistic effect which was not increased further by addition of higher amounts of biuret.
	www.actahort.org /books/329/329_51.htm (256 words)

	Preparation of biuret-containing polyisocyanates - Patent 7022874
		A process as claimed in claim 1, wherein the biuretizing agent (b) is a tertiary alcohol or a mixture of a tertiary alcohol and up to 80 mol % of water based on the sum of the components of the mixture.
		The difficulty of preparing homogenous mixtures of water and the isocyanate means that in the course of this reaction, in practice, local excesses of water always result in the formation of greater or lesser proportions of insoluble polymeric urea-containing compounds which are deposited in the reaction vessel or in the off-gas space.
		In accordance with the invention, the isocyanate (a) is reacted with the biuretizing agent (b) in the presence of catalytic amounts of a stabilizer (c).
	www.freepatentsonline.com /7022874.html (2432 words)

	Process for the preparation of aromatic polyisocyanates containing urea and/or biuret groups - Patent 4618706
		This invention relates to a process for the preparation of aromatic polyisocyanates containing urea and/or biuret groups, optionally in the form of a mixture of homologues and/or isomers, by the reaction of aromatic diisocyanates with diamines having primary or secondary amino groups at about 20.degree.
		Such urea and/or biuret bonds are normally obtained by the action of water on polyisocyanates, which entails the loss of valuable isocyanates.
		The reaction mixture of Example 4 was prepared by a preferred method according to the invention in that the reaction was carried out using 1 g of toluene sulphonic acid ethyl ester and 0.2 g of zinc acetyl acetonate and followed by 4 hours stirring at 100.degree.
	www.freepatentsonline.com /4618706.html (3617 words)

	Purification and Characterization of TrzF: Biuret Hydrolysis by Allophanate Hydrolase Supports Growth -- Shapir et al. ...
		ADP, AtzF, was also shown to hydrolyze biuret slowly.
		biuret and allophanate are consecutive metabolites in cyanuric
		In vitro, TrzF was shown to hydrolyze biuret to liberate 3 mol
	aem.asm.org /cgi/content/abstract/72/4/2491 (330 words)

	biuret (Site not responding. Last check: 2007-10-29)
		The biuret reaction is a method that can be used to determine the amount of soluble protein in a solution.
		Record the data from the biuret reactions on the standard protein concentrations in a spreadsheet, so that the first column contains the protein concentration and the second column is the corresponding Optical Density (OD), measured with the spectrophotometer.
		The line on the graph relates the protein concentration to the OD of the biuret reaction.
	www.hamline.edu /depts/biology/courses/biocon2/biuret.html (795 words)

	Biuret - Wikipedia, the free encyclopedia
		It is a white solid soluble in hot water and decomposing at 186–189 °C.
		Biurets can be prepared by trimerization of isocyanates.
		The biuret reagent is used in the biuret protein assay, a chemical test for proteins not because the reagent contains biuret but because both biuret and proteins have the same response to copper.
	en.wikipedia.org /wiki/Biuret (170 words)

	Lebefu Trading > Commodities > Fertilisers > Urea 46 (Site not responding. Last check: 2007-10-29)
		Biuret content is typically around 0.3%, although urea of foreign origin appears to be higher.
		Biuret converts to ammonia, but conversion is much slower than for urea.
		Since biuret remains in the soil for several weeks, the potential for seed damage continues beyond the brief period of conversion of urea to ammonia.
	www.eworkonline.com /Default.aspx?tabid=503 (1208 words)

	WKU Biology Protein Assay animation
		The biuret reagent (copper sulfate in a strong base) reacts with peptide bonds (which join amino acids to form Proteins) and changes color when it does so.
		Since the Biuret solution components absorb some amount of light themselves, this amount must be accounted for by “subtracting” it from the total absorption for the protein alone.
		A Spectophotometer is used to measure the absorbance @ 560 nm of 5 samples with known concentration to establish a standard curve.
	bioweb.wku.edu /courses/Biol121/Protein/Biuret.asp (678 words)

	Purification of Lysozyme, Part 1
		At the third meeting, determine the contents of your fractions, including a) protein concentration (biuret method), b) lysozyme concentration (using and enzyme assay), and conductivity (to map progress of the salt gradient).
		In this part of the lysozyme-purification project, you will learn how to measure protein concentration by the biuret method, which entails reacting the protein with a color-producing reagent and measuring the absorbance of the resulting solution.
		Copper (II) ion in the biuret reagent forms a purple complex with peptide bonds in the protein.
	www.usm.maine.edu /~rhodes/BiochemLab/Text/HdtPurLys/HDTPurLys01.html (1344 words)

	Serum Protein (Site not responding. Last check: 2007-10-29)
		We use the Biuret method, which is the predominant method used to measure serum protein.
		The Biuret method is a colorimetric procedure, which can be purchased from Sigma, or be easily made from a mixture of six chemicals.
		The Biuret reagent is based on a reaction between copper and molecules with at least 2 peptide bonds.
	www.unm.edu /~rrobergs/serum_protein.htm (551 words)

	NONPROTEIN NITROGEN IN THE NUTRITION OF RUMINANTS
		Using an in vitro fermentation procedure for evaluating various nitrogen sources, Belasco (1954) found that biuret supported only 7 percent as much cellulose digestion as an equal amount of nitrogen from urea, and he suggested that biuret was not a useful nitrogen source for rumen micro-organisms.
		Biuret also gave slightly lower nitrogen retention with bull calves and appeared to be slightly inferior to urea for lactating cows but the differences were very small.
		Biuret is not available commercially so that its utilization has no practical significance at present.
	www.fao.org /DOCREP/004/AC149E/AC149E04.htm (4778 words)

	Week 3 (Site not responding. Last check: 2007-10-29)
		To use the biuret test which was learned in a previous lab to quantitatively analyze a protein.
		The biuret test relies on the reaction between copper ions and peptide bonds in an alkaline solution.
		It is possible to use the biuret reaction to determine the concentration of proteins because (for most proteins) peptide bonds occur with approximately the same frequency per gram of material.
	virtual.parkland.edu /hleuszler/bio141/wk3.htm (1841 words)

	Biuret reagent - Wikipedia, the free encyclopedia
		The Biuret Reagent is made of sodium hydroxide and copper sulphate.
		The reagent is commonly used in a Biuret protein assay, a colorimetric assay used to determine protein concentration.
		The biuret assay does not in fact use biuret (biuret is a compound formed from two urea molecules), but is thus named as it detects the amine bond between the urea molecules or between amino acids.
	en.wikipedia.org /wiki/Biuret_reagent (171 words)

	Biuret's Test (Site not responding. Last check: 2007-10-29)
		In this test a violet-purple color is produced when cupric ions complex with peptide bonds under alkaline conditions.
		Biuret reagent (Add 7.5 g CuSO4(5H2O), 100 ml 50% (w/w) NaOH, and 25 g KNa tartrate to a 1 L volumetric flask and take to volume with d.
		To a sixth tube add the equivalent mixture using 5cc of unknown instead of the peptone.
	www.racerocks.com /biology/syllabus/biochem/biurets.htm (444 words)

	Protein determination by the biuret method
		The principle of the biuret assay is similar to that of the Lowry, however it involves a single incubation of 20 min.
		The biuret is a good general protein assay for batches of material for which yield is not a problem.
		As with most assays, the Biuret can be scaled down for smaller cuvette sizes, consuming less protein.
	www.ruf.rice.edu /~bioslabs/methods/protein/biuret.html (445 words)

	Biuret Reagent Solution, 4oz. for sale. Buy from The Science Company.
		Home > Chemicals > General Chemicals > Biuret Reagent Solution, 4oz.
		Biuret Reagent is an aqueous solution of biuret (allophanamide) treated with cupric sulfate and sodium hydroxide.
		Add 3 drops of Biuret reagent solution to each test tube.
	secure.sciencecompany.com /Biuret-Reagent-Solution-4oz-P6410C670.aspx (158 words)

	Reagents
		It gives a slightly stronger reaction, and considerably faster (30-60 seconds), but is much less stable than the recipe we've come up with, and the fumes are much more a problem with concentrated than with 6 M HCl.
		Biuret Reagent: Add, with stirring, 300 mL of 10% (w/v) NaOH to 500 mL of a solution containing 0.3% copper sulfate pentahydrate and 1.2% sodium potassium tartrate, then dilute to one liter.
		The reagent is stable for a few months but not a year.
	faculty.mansfield.edu /bganong/biochemistry/reagents.htm (1106 words)

	Biuret
		From the name of a specific chemical substance, biuret, that gives a strong positive reaction with the biuret reagent.
		More standard synonoms for Biuret are "Carbamyl Urea" and "Imidodicarbonic diamide".
		Note that Biuret is not an exact analog of a di-amino acid, which would have an alpha carbon between the caronyls.
	bio.classes.ucsc.edu /bio20L/info/content/protein/answers/biuret.htm (79 words)

	Identifying Nutrients Gizmo \| ExploreLearning
		Use a variety of real‑world lab tests to analyze common food samples in order to determine if the food is a carbohydrate, a protein, or a lipid.
		Tests that can be performed include: benedict, lugol, biuret, and sudan red.
		Which of the following would test positive in the Biuret test, and negative in the Sudan red test?
	www.explorelearning.com /index.cfm?method=cResource.dspView&ResourceID=452 (276 words)

	biuret
		% biuret config(biuret,[ chain([ amine, keto, nit(3,hyd), keto, amine])]).
		The Terminals for all the Config Rules are in Prolog Definite Clause Grammar (DCG) form.They can be checked in the Manual here.
		Doug Markham of the Institute for Cancer Research, Fox Chase Cancer Center,Philadelphia, PA, has contributed the following structure for biuret.
	www.biocheminfo.org /klotho/html/biuret.html (179 words)

	ADM Alliance Nutrition
		Due to Biuret's unique chemical properties, Biuret is released more gradually in the rumen compared to urea.
		Biuret gives you a more cost effective protein source than urea and gives a higher level of safety against ammonia toxicity.
		Mintrate XL Tubs utilize multiple source proteins, scientifically researched levels of base and trace minerals with vitamins, a low level of urea, and Biuret in almost all tubs to maximize forage digestion in the rumen which leads to optimum animal performance.
	www.admani.com /alliancebeef/MintrateXL_Tub.htm (878 words)

	Biuret (Site not responding. Last check: 2007-10-29)
		The principle of the biuret assay is similar to that of the Lowry, however it involves a...
		The Biuret of HDI is made through the condensation of 3 HDI molecules with 1 water molecule...
		It is a mixture of compounds including biuret and small amounts of triuret, cyanuric acid, and urea, and is formed by...
	testingforvitaminc.scarvitaminc.com /biuret (708 words)

	Sampling and Analytical Methods: HDI Biuret (Biuret of Hexamethylene Diisocyanate) PV2030
		The type of work most liable to HDI biuret exposure is spray painting with polyurethane paints -- for example, of airplanes (Reference 5.1) and of cars (Reference 5.2).
		Apply a correction factor of 0.4943 (F.W. of HDI biuret 478/F.W. of the derivative 967) to express the concentrations in terms of HDI biuret.
		The concentration of HDI biuret for a sample is determined from the calibration curve.
	www.osha.gov /dts/sltc/methods/partial/pv2030/2030.html (1118 words)

	Purification of Lysozyme, Part 3
		Use the biuret reaction to determine the protein concentration in 1) the egg-white extract, 2) the column wash, and 3) every third chromatographic fraction starting with number 3 (3, 6, 9,...).
		To bring the concentrations of egg-white extract into the proper range for the biuret reaction, dilute 1 mL of egg-white extract to 5 ml with Buffer A, making this mixture a 1:40 dilution of the original egg white.
		Use the biuret calibration equation from the biuret experiment to determine the protein concentration (mg/mL) in the column wash and all fractions.
	www.usm.maine.edu /~rhodes/BiochemLab/Text/HdtPurLys/HDTPurLys03.html (3027 words)

	Urea
		Biuret levels of 2% can be tolerated in most fertilizer programs.
		Because citrus, pineapple, and other crops are sensitive to biuret in urea applied as a foliar spray, less than 0.25% biuret is recommended.
		Urea high in biuret should not be placed near or in the seed row.
	nue.okstate.edu /N_Fertilizers/Urea.htm (932 words)

	[No title] (Site not responding. Last check: 2007-10-29)
		One drop of each of the three indicator solutions (iodine, Sudan III and Biuret & copper sulfate) was added to each sample solution to determine how that sample solution (and that type of macromolecule) would react with each specific indicator.
		The indicator solution that could best be used to show the presence of protein was the biuret & copper sulfate solution, since protein reacted with the biuret & copper sulfate to form a dark purple solution.
		The iodine indicator reacted with the vitamin C to produce a colorless solution, which can be contrasted with the yellow control, while the biuret and copper sulfate produced a yellow solution that differed from the light blue control.
	www.csupomona.edu /~srkoukol/BIO115L/formallab.doc (584 words)

	Complete Nucleotide Sequence and Organization of the Atrazine Catabolic Plasmid pADP-1 from Pseudomonas sp. Strain ADP ...
		Cyanuric acid is hydrolyzed to biuret and is hypothesized to be subsequently hydrolyzed to urea, carbon dioxide, and ammonia.
		The degradation of biuret was also examined by HPLC analyses.
		TLC analyses were performed as described by Radosevich (44) to detect the products of biuret degradation.
	jb.asm.org /cgi/content/full/183/19/5684 (7498 words)

	Science News for Kids: ScienceFairZone
		John consulted an expert, Robert Krueger, who suggested that he look at the effect of biuret, a chemical contained in the urea fertilizer he was using.
		John concluded that the use of a high biuret area (HBU) fertilizer at low concentrations might be a viable foliar fertilizer for young citrus trees.
		The added benefit of HBU fertilizer is that biuret degrades seven times more slowly than urea, reducing groundwater contamination while serving the need to advance the growth of the citrus trees.
	www.sciencenewsforkids.org /articles/20040225/ScienceFairZone.asp (318 words)

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