scholarly journals HISTOCHEMICAL AZO COUPLING OF PROTEIN HISTIDINE BRUNSWIK'S NITRATION METHOD

1972 ◽  
Vol 20 (11) ◽  
pp. 929-937 ◽  
Author(s):  
R. D. LILLIE ◽  
P. T. DONALDSON

The xanthoproteic reaction is accomplished with only 20% HNO3 with glacial acetic acid (HAc) as the solvent; in water 40% HNO3 is required. Tyrosine and 3-mononitrotyrosin readily azo-couple in alkaline solution with fresh p-nitrodiazobenzene in vitro; 3,5-dinitrotyrosine does not. In vitro p-nitrodiazobenzene at pH 8.5 does not couple with histidine, tryptophan or tyrosine after overnight nitration in tetranitromethane (TNM)-pyridine-0.1 N HCl 1:20:40. Histochemical nitration of tissue adequate to prevent the p-diazobenzenesulfonic acid, pH 1-0.02% azure A sequence reaction of hair medulla and arterial elastin of man, dog and rodents can be achieved by 40% HNO3 in glacial acetic acid-acetic anhydride (Ac2O) mixtures. Acetic anhydride should be 10% only, to restrict evolution of brown oxides of nitrogen and prevent undue section losses. Exposures of 4 hr at 3°C to 4:5:1 HNO3:HAc:Ac2O are effective and well tolerated. Nitration is also effectively accomplished by 6-hr 25°C exposures to mixtures of 1% tetranitromethane-pyridine and two volumes of water (pH 8.2) or 0.1 N HCl (pH 6.6). Even 10% TNM in dry pyridine and 2.5% in 16.3% pyridine alcohol (6 hr), 3°C exposures gave only partial tyrosine blockades. The pyridine-water TNM mixtures also prevented the Morel-Sisley tyrosine reaction and, with greater exposures, the postcoupled benzylidene indole reaction of tryptophan as well. Sites reactive to diazobenzenesulfonic acid-azure A after the best nitrations are probably assignable largely to histidine, though the presence of some unblocked tryptophan, purines and other reactive substances must be considered.

1974 ◽  
Vol 23 (7) ◽  
pp. 420-422
Author(s):  
Yoshiharu MATSUBARA ◽  
Yoshihito FUJIHARA ◽  
Yutaka SAKAI ◽  
Makoto SANO

1989 ◽  
Vol 42 (8) ◽  
pp. 1281 ◽  
Author(s):  
MR Grimmett ◽  
ST Hua ◽  
KC Chang ◽  
SA Foley ◽  
J Simpson

Nitration of 4-nitroimidazole in acetic anhydride/glacial acetic acid gives 1,4-dinitroimidazole. The crystal and molecular structure of this compound have been determined by direct methods. Crystals are orthorhombic; P212121, a 5.853(3), b 9.591(8), c 10.392(5) � , V 583.4(7) � 3 , Dm 1 .76 g cm-1, Dc, 1 .80 g cm-1 (Z = 4); λ 0.71069 � ; T 173 K. The structure was refined to R = 0.048 for 926 reflections [I > 2 σ(1)]. Both 2-methyl-4-nitro- and 5-methyl-4-nitro-imidazoles N-nitrate under the same conditions. When heated in solution at 100-140�C 1,4-dinitro- and 2-methyl-1,4-dinitro-imidazoles rearrange to give C-nitro isomers and some denitration products, but 5(4)-methyl-1,4(5)-dinitroimidazole failed to give identifiable products.


2010 ◽  
Vol 65 (12) ◽  
pp. 1509-1515 ◽  
Author(s):  
Manjunatha Kumsi ◽  
Boja Poojary ◽  
Prajwal Lourdes Lobo ◽  
Nalilu Suchetha Kumari ◽  
Anoop Chullikana

The key precursor rac-2-(4-isobutylphenyl)ethyl-1,2,4-triazole-5-thione (3) was synthesized in good yield from Ibuprofen (1). One-pot three-component reactions of 3 with 5-aryl-furan-2-carboxaldehydes/ substituted aromatic aldehydes and monochloroacetic acid in acetic acid in the presence of acetic anhydride and anhydrous sodium acetate afforded substituted thiazolo[3,2-b][1,2,4]triazole derivatives 4 and 5. The structures of the newly synthesized compounds were elucidated by elemental analyses and spectral data. The compounds were tested for their in-vitro antimicrobial activities.


2010 ◽  
Vol 7 (1) ◽  
pp. 295-298 ◽  
Author(s):  
B. C. Revanasiddappa ◽  
R. Nagendra Rao ◽  
E. V. S. Subrahmanyam ◽  
D. Satyanarayana

A new series of chalcones (3a-j) were synthesized by condensation of simple aldehydes with substituted acetophenones in presence of alkali. The resulted chalcones upon cyclization in presence of glacial acetic acid with isoniazid (INH) will yields the title compounds (4a-j). The newly synthesized compounds were assigned on the basis of IR,1H NMR, and Mass spectral data. All the final compounds were evaluated for theirin vitroantimicrobial activity.


2011 ◽  
Vol 74 (8) ◽  
pp. 1348-1352 ◽  
Author(s):  
R. A. OTTO ◽  
I. PAKER ◽  
L. BANE ◽  
S. BEAMER ◽  
J. JACZYNSKI ◽  
...  

During mechanical fish processing, a substantial amount of protein is discarded as by-products. Isoelectric solubilization and precipitation (ISP) is a process that uses extreme pH shifts to solubilize and precipitate protein from by-products to recover previously discarded protein. Typically, strong acids are used for pH reduction, but these acids do not have a pasteurization effect (6 log reduction) on bacterial load; therefore, organic acids were used during ISP processing to test the impact on Listeria innocua concentrations. Headed and gutted rainbow trout (Oncorhynchus mykiss) were inoculated with L. innocua, homogenized, and brought to the target pH with granular citric acid (pH 2.0 and 2.5) or glacial acetic acid (pH 3.0 and 3.5). Proteins were solubilized for 10 min at 4°C, and insoluble components (e.g., skin and insoluble protein) were removed by centrifugation. The remaining solution was pH shifted to the protein isoelectric point (pH 5.5) with sodium hydroxide, and precipitated protein was separated from the water. Microbial cells for each component (proteins, insolubles, and water) were enumerated on modified Oxford agar (MOX) and tryptic soy agar with 6% yeast extract (TSAYE). The sums of the surviving cells from each component were compared with the initial inoculum levels. No significant differences were observed between results obtained from TSAYE and from MOX (P > 0.05). Significant reductions in microbial populations were detected, regardless of pH or acid type (P < 0.05). The greatest reduction was at pH 3.0 with glacial acetic acid, resulting in a mean reduction of 6.41 log CFU/g in the recovered protein and 5.88 log CFU/g in the combined components. These results demonstrate the antimicrobial potential of organic acids in ISP processing.


1951 ◽  
Vol 29 (5) ◽  
pp. 377-381 ◽  
Author(s):  
A. Gillies ◽  
H. L. Williams ◽  
C. A. Winkler

This reaction at 35°C. exhibits a behavior indicative of the presence of an intermediate in the reaction. Reaction of paraformaldehyde and ammonium nitrate in glacial acetic acid resulted in the isolation of hexamine dinitrate. Evidence is presented to indicate that formation of hexamine dinitrate, accompanied by the production of nitric acid, is responsible for the production of RDX in the acetic anhydride system.


1986 ◽  
Vol 69 (4) ◽  
pp. 620-624 ◽  
Author(s):  
N Aziz Zakhari ◽  
K Artur Kovar

Abstract Trifluoromethyl sulfonic acid in glacial acetic acid has been compared with perchloric acid as a titrant in 4 solvent systems: glacial acetic acid, acetic anhydride, a mixture of both, and acetone. The comparison was limited to the determination of halides of nitrogenous bases with and without the use of mercury(II) acetate reagent. The results of the visual titrations showed that both acids are comparable tit rants. However, trifluoromethyl sulfonic acid proved to be superior to perchloric acid in potentiometric titrations carried out in acetic acid-acetic anhydride mixtures. Moreover, the nonoxidizing properties exhibited by trifluoromethyl sulfonic acid proved advantageous over perchloric acid in the visual detection of end points in the titration of phenothiazine derivatives in anhydrous acetic acid, using crystal violet indicator.


2018 ◽  
Vol 4 (1) ◽  
Author(s):  
M. Topan Darmawan ◽  
Muthia Elma ◽  
M. Ihsan

Selulosa asetat merupakan senyawa turunan selulosa yang sering digunakan sebagai serat, membran, dan film fotografi dalam industri. Tujuan dari penelitian ini adalah mengetahui pengaruh waktu asetilasi terhadap karakter selulosa asetat yang dihasilkan. Adapun proses yang digunakan dalam penelitian ini adalah proses cellanase dengan bahan baku tandan kosong kelapa sawit (TKKS). Tahapan reaksinya adalah aktivasi, asetilasi, dan hidrolisis. Aktivasi dilakukan di dalam labu leher tiga dengan penambahan asam asetat glacial 50 mL dan diaduk selama 3 jam pada kecepatan 125 rpm. Selanjutnya ditambahkan asetat anhidrida 15 mL sebagai agen asetilasi. Asetilasi dilakukan dengan variasi waktu, 2; 2,5; 3; dan 3,5 jam. Pada tahapan hidrolisis, ditambahkan air 2 mL dan asam asetat glacial 5 mL. Reaksi berlangsung selama 30 menit. Selanjutnya ditambahkan 1 gram natrium asetat untuk netralisasi yang berlangsung selama 5 menit. Kemudian dilakukan pencucian sampai bau asam asetat hilang. Tahapan terakhir adalah pengeringan yang dilakukan dengan suhu 55ºC selama 6 jam. Produk yang dihasilkan kemudian dianalisis kadar air, kadar asetil, rendemen dan gugus fungsi menggunakan analisa FTIR. Selulosa asetat yang terbaik diperoleh pada waktu asetilasi selama 2,5 jam dengan  kadar  asetil  40,36%, kadar  air  4.43%,  dan  rendemen 153,8%.Kata kunci: cellanase, selulosa, selulosa asetat. Cellulose acetate is a cellulose derivative which is often used as a fiber, membrane, and photographic film in industry. The  objectives  of  this  study  were  to determine the effect of acetylation time on the character of cellulose acetate. The process used in this study is the process of cellanase with α-cellulose of empty palm oil bunches materials. Stages of reaction are activation, acetylation, and hydrolysis. Activation was performed in a three-neck flask with the addition of 50 mL glacial acetic acid and stirred for 3 hours at 125 rpm. Then added 15 mL acetic anhydride as acetylation agent. Acetylation was performed by varying the time, 2; 2.5; 3; And 3.5 hours. At the hydrolysis stage, 2 mL of water and 5 mL glacial acetic acid were added. The reaction lasts for 30 minutes. Then added 1 gram of sodium acetate for neutralization lasts 5 minutes. then do the washing up to the smell of acetic acid disappeared. The final stage is the drying is done at a temperature of 55ºC for 6 hours. The resulting product was then analyzed for water content, acetyl content, rendement and functional groups using FTIR analysis. Cellulose acetate are best obtained at the time of acetylation for 2.5 hours with acetyl content of 40.36%, water content 4:43%, and a yield of 153.8%.Keywords: acetate cellulose, cellanase, cellulose.


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