Cyanogen specificity

Cyanogenic glycosides are potentially toxic because they liberate hydrogen cyanide on enzyme-catalyzed or acidic hydrolysis. Give a mechanistic explanation for this behavior for the specific cases of... 

Several highly specific chemical methods of proteolysis are available, the most widely used being cyanogen bromide (CNBr) cleavage. CNBr acts upon methio-... 

Cyaneisen, n. iron cyanide, -kalium, n. potassium ferrocyanide, -verbindungt /. iron cyanogen compound, specif, a ferrocyanide. 

Proteins can be cleaved specifically at the amide bond on the carboxyl side of methionine residues by reaction with cyanogen bromide. BrC=N. 

Cyanide and thiocyanate anions in aqueous solution can be determined as cyanogen bromide after reaction with bromine [686]. The thiocyanate anion can be quantitatively determined in the presence of cyanide by adding an excess of formaldehyde solution to the sample, which converts the cyanide ion to the unreactive cyanohydrin. The detection limits for the cyanide and thiocyanate anions were less than 0.01 ppm with an electron-capture detector. Iodine in acid solution reacts with acetone to form monoiodoacetone, which can be detected at high sensitivity with an electron-capture detector [687]. The reaction is specific for iodine, iodide being determined after oxidation with iodate. The nitrate anion can be determined in aqueous solution after conversion to nitrobenzene by reaction with benzene in the presence of sulfuric acid [688,689]. The detection limit for the nitrate anion was less than 0.1 ppm. The nitrite anion can be determined after oxidation to nitrate with potassium permanganate. Nitrite can be determined directly by alkylation with an alkaline solution of pentafluorobenzyl bromide [690]. The yield of derivative was about 80t.with a detection limit of 0.46 ng in 0.1 ml of aqueous sample. Pentafluorobenzyl p-toluenesulfonate has been used to derivatize carboxylate and phenolate anions and to simultaneously derivatize bromide, iodide, cyanide, thiocyanate, nitrite, nitrate and sulfide in a two-phase system using tetrapentylammonium cWoride as a phase transfer catalyst [691]. Detection limits wer Hi the ppm range. 

The chemical speciation of cyanides varies according to their source. Specific terms used to describe cyanide include free cyanide, cyanide ion, simple cyanides, complex cyanides, nitriles, cyanogens, and total cyanide. The most common forms of cyanide in the environment are free cyanide, metallocyanide complexes, and synthetic nitriles. A brief description of each cyanide species follows (Smith et al. 1978, 1979 Towill et al. 1978 Egekeze and Oehme 1980 USEPA 1980, 1989 Davis 1981 Leduc 1981, 1984 Leduc etal. 1982 Simovic and Snodgrass 1985 Ballantyne 1987a Homan 1987 Marrs and Ballantyne 1987). 

ANDERSEN, M.D., M0LLER, B.L., Cytochromes P450 from Cassava (Manihot esculenta Crantz) catalyzing the first steps in the biosynthesis of the cyanogenic glucosides linamarin and lotaustralin cloning, functional expression in Pichia pastoris and substrate specificity of the isolated recombinant enzymes, J. Biol. Chem., 2000,275, 1966-1975. 

Spectra to be analyzed via PMF are derived from a protein sample been treated with an enzyme (e.g., trypsin) or other chemical (cyanogen bromide) with specific cleavage activity. The experimental m/z values for each peptide are converted into peptide masses and compared with the theoretical mass... 

Industrial Agents Chemicals manufactured for industrial purposes rather than to specifically kill or maim human beings. Hydrogen cyanide, cyanogen chloride, phosgene, and chloropicrin are industrial chemicals that can be military agents as well AC, CK, CG, and PS. Many herbicides and pesticides are industrial chemicals that also can be chemical agents. 

Bradycardia, arrhythmias, and T-wave abnormalities were observed in monkeys exposed to 100 ppm hydrogen cyanide (96 ppm cyanide) for 30 minutes (Purser et al. 1984). Increased cardiac-specific creatinine phosphokinase activity was measured in blood samples from rats 2 hours after 12.5 minutes of exposure to 200 ppm hydrogen cyanide (192 ppm cyanide) for 20 days at 4-day intervals (O Flaherty and Thomas 1982). However, no treatment-related changes were found in the hearts at histopathology. In addition, no cardiovascular effects were reported at necropsy in rats and monkeys exposed to 25 ppm cyanogen (50 ppm cyanide) for 6 months (Lewis et al. 1984). 

Niacin can be detected by UV, ED, or FLD. UV is a widespread technique but it needs a longer preparation step and it does not reach high sensitivity. The FLD is more sensitive but it needs a pre or postcolumn derivatization to make niacin fluorescent. Krishnan et al. [599] describe a postcol-umn derivatization using cyanogens bromide and p-aminophenol, but this method involves toxic reagents. Mawatari et al. [600], instead, propose a fast, highly specific derivatization procedure, which involves UV irradiation at 300 nm in the presence of hydrogen peroxide and copper(II) ions. 

A few syntheses of specific substituted 3,3 -bipyridines have been reported. 6,6 -Dialkyl-3,3 -bipyridines have been shown to be one of the products of the reaction of l-lithio-2-alkyl-l,2-dihydropyridines with perhalometh-anes, cyanogen bromide, or bromine. In an interesting double... 

Amine-Reactive Methods Amine groups is often used for the immobilization of proteins and peptides. Specific methods are cyanogen bromide method, reductive amination, N-hydroxysuccinimide technique, and carbonyldiimidazole method. 

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