sodium benzoate and ascorbic acid reaction

Ngày tải lên: 05/09/2013, 08:40

... analogues and other longer ligands are required to establish the mechanism of ligand binding and product formation. Ascorbic acid inhibits the functional activity of HylP2 Ascorbic acid has previously ... substrate. Ascorbic acid binding Ascorbic acid (Fig. 1A) inhibits the activity of HylP2. The structure of the complex of HylP2 with ascorbic acid shows that three molecules of ascorbic acid bind to ... ascorbic acid. Catalytic site The structures of native protein HylP2 and its com- plexes with ascorbic acid and lactose revealed the presence of three long concave surfaces on the triple-stranded...

Ngày tải lên: 23/03/2014, 04:21

Ngày tải lên: 18/06/2014, 19:20

Ngày tải lên: 20/06/2014, 03:20

Ngày tải lên: 07/08/2014, 18:21

Ngày tải lên: 05/09/2013, 10:17

... oil and shikimic acid from star anise fruits. With this method, obtaining yield of essential oil and shikimic acid respectively are 9.5% and 5.6% (essential oil content and shikimic acid ... Sciences and Technology 26 (2010) 110-113 113 for obtaining simultaneously essential oil and shikimic acid from star anise fruits. The yield of essential oil and shikimic acid were 9.5% and ... N 0 1, N 0 2 and N 0 3 were shown at table 1 and table 2. Table 1. Obtaining simultaneously essential oil and shikimic acid from star anise fruits by methods N 0 1, N 0 2 and N 0 3 Star...

Ngày tải lên: 12/02/2014, 17:20

... before as important step in the biosynthesis of the lantibiotics epidermin and mersacidin catalyzed by the LanD enzymes EpiD and MrsD, respectively [8–10]. Flavin- dependent oxidative decarboxylation ... N210K and copurification of the 4¢-phosphopantothenoyl- CMP intermediate. His-CoaB proteins (His-CoaB and His-CoaB N210K) were puri- fied from E. coli cell extracts by Ni-nitrilotri- acetic acid and ... Escherichia coli and most eubacteria, the synthesis of 4¢-phosphopantetheine, which is also the key reaction in coenzyme A biosynthesis, is catalyzed from 4¢-phospho- pantothenate and cysteine by...

Ngày tải lên: 19/02/2014, 12:20

... RNase H domain and an APase domain. The RNase H and APase activities of the full length SCO2299 protein depend on its N-terminal RNase H domain and C-ter- minal APase domain, respectively, and do not ... plates containing 50 lgÆ mL )1 ampicillin and 30 lgÆmL )1 chloramphenicol, and incubated at 30 °C and 42 °C. Plasmid constructions, overproductions and purifications Plasmids for overexpression ... dimethylbenzimi- dazole, 200 lm PIPES as an internal standard, and 2 lgof protein samples in a final volume of 100 lL. The reaction mixture was incubated for 10 min at 37 °C and transferred to 400 lL cold methanol....

Ngày tải lên: 19/02/2014, 18:20

... ligand. The corresponding spectral changes in the Soret band were therefore followed by stopped-flow and rapid-scan techniques, and the observed first-order rate constants of k out ¼ 25 s )1 and k in ¼ ... resistance to acidic autoxidation, we conclude that T. akamusi hemoglobin VII, the major component, can play an important role in O 2 transport and storage against the extremely acidic and hypoxic ... door for ligand entry. J. Mol. Biol. 207, 459–463. 23. Tian, W.D., Sage, J.T. & Champion, P.M. (1993) Investigations of ligand association and dissociation rates in the ÔopenÕ and ÔclosedÕ states...

Ngày tải lên: 20/02/2014, 23:20

... amino acid sequence of GALA revealed very high similarity to the endogalactanases of A. tubingensis (95.7% amino acid sequence identity) and A. aculeatus (78.9% amino acid sequence identity) and ... min D -galactose, D -galactobiose and D -galactotetraose were used as standards to identify the D -galactose and D -galacto-oligosaccharides. The calculated areas for D -galactose and D -galacto-oligosaccharides ... endogalactanases (between 21% and 28% amino acid sequence identity). This is illustrated by a CLUSTALW analysis [29] of the deduced amino acid sequences of GALA and b-1,4-endogalactanases of Aspergillus...

Ngày tải lên: 21/02/2014, 01:21

... uncharged polar amino acids (i.e. Q, N, S, and T) and an increase in charged amino -acid residues (i.e. K, E, and R) in hyperthermophilic proteins. As S and T can catalyze the deamination and backbone ... The amounts of fructose and xylulose produced were determined using the cysteine/carbazole/sulfuric acid method. Absorbance was measured at 537 nm and 560 nm for xylulose and fructose, respectively. ... 0.981, is based on the elution data of the 200, 150, and 66 kDa protein standards. Linear regressions (1) and (2) give molecular masses of 200 and 177.5 kDa, respectively, for BLXI. 6294 C. Vieille...

Ngày tải lên: 22/02/2014, 07:20

... complex 16 . Amplification reaction was typically performed in a 50µl reaction mix containing 0.25nmoles of forward and reverse primers, 2mM final concentration of dNTP, 1.5 U of Taq polymerase in 1X buffer and proteinase ... These cases were as follows, two each of asthma, pneumonia and cancer lung, one each of post CABG, COPD and lung abscess and 12 with cough and cold. All samples from these individuals had tested ... investigations, namely smear, culture and PCR. Sample processing, culture and PCR Samples were processed using either Petroffs’s method or N-acetyl-L-cysteine -sodium hydroxide method 15 . A small...

Ngày tải lên: 06/03/2014, 04:20

... Differential effects of ligand-activated RARa and RXRa on the promoter activity of the hGnRH II gene in TE671 and JEG-3 cells. In vivo effect of RARa and RXRa with their ligands, ATRA and 9-cisRA, on the ... TE671 medulloblastoma and JEG-3 placenta choriocarcinoma cells. Supershift and chromatin immunoprecipitation assays showed in vitro and in vivo binding of NF-jB subunit p65 and the retinoic acid receptors, RARa and RXRa, ... PCR. Treatment of cells with the RARa ⁄ RXRa ligands, all-trans retinoic acid and 9-cis-retinoic acid, reduced and increased GnRH II gene expression in TE671 and JEG-3 cells, respectively. Taken together,...

Ngày tải lên: 16/03/2014, 10:20

... or “partner” in meeting the HPB mandate; and • a lack of new criteria for “safety”, new methods for post marketing evaluation of drugs and devices and social and ethical evaluation of new initiatives. ... drug reactions to patients and health-care providers. The jury’s first recommendation called on Health Canada to set up a joint body to review, improve and standardise all communication tools and ... Abraham and Paul Taylor, “Drug reactions kill thousands: researchers”, The Globe and Mail, April 15, 1998. 46 Namrata Bains, MSc; Duncan Hunter, PhD, Adverse reporting on adverse reactions,...

Ngày tải lên: 22/03/2014, 11:20

... co-distilled with distilled water and reduced using sodium borohydride. Excess sodium borohydride was destroyed by adding 2 m acetic acid and again repeatedly co-distilled with methanol and dried in a dessicator. ... into SFC and FFC, SFD, FFD and FFD-500 groups. SFC and SFD groups received AIN-76 basal diet, whereas FFC and FFD groups received AIN-76 diet, wherein starch was replaced with 5% wheat bran and 2.5% ... neutral sugars like mannose and galactose and amino sugar as N-acetylglucos- amine, along with sialic acid which accounted for  22 and 35% of total carbohydrate content in SFC and SFD groups, respectively. Purification...

Ngày tải lên: 22/03/2014, 17:20

Ngày tải lên: 22/03/2014, 18:20

... origin of the later dysfunctions. Ascorbic acid is known to selectively dissolve the quartz surface. During the reaction, ascorbic acid progressively disappears and hydroxyl radicals are generated ... through the expression and activity of the enzyme cyclo-oxygenase-2 (COX-2). COX-2 expression and prostaglandin secretion were enhanced in cells incubated with ascorbic acid- treated quartz. In ... a Gel Dryer 543 (Bio-Rad), and the radioactive complexes were visualized and quantified with the Packard Cyclone Stor- age Phosphor System and optiquant acquisition and analysis software (PerkinElmer...

Ngày tải lên: 23/03/2014, 10:20

... different concentrations of ascorbic acid. (B) 100 l M ascorbic acid. (C) Solid line, difference spectrum [(30 l M T4 DNA + 100 l M ascorbic acid) solution ) (100 l M ascorbic acid) solution]. Broken ... the absence and presence of ascorbic acid. Depending on the concentration of ascorbic acid, DNA molecules exhibit intrachain and translational Brownian motion with differ- ent conformations. Without ascorbic ... of the action of ascorbic acid on DNA Ascorbic acid is present in human blood at a concentration of % 50 l M [31,32]. Moreover, the concentration of ascorbic acid in human cells and tissues can...

Ngày tải lên: 23/03/2014, 21:20

... procedures Materials Analytical reagent-grade sodium hydroxide (50% w ⁄ w), sodium acetate, sulfuric acid and sodium chloride were obtained from J.T. Baker (Deventer, The Netherlands). Acetonitrile was obtained ... Neu5Ac and the adjacent hexose. No relevant ring fragments were observed between C 2 and C 3 , which is consistent with a 1–3 linkage between Hex and HexNAc. The ring fragment ions 0,2 A 4 and 2,4 A 4 , ... fragment ions 0,2 A 4 and 2,4 A 4 , and the lack of 0,3 A 4 , are indica- tive of a 1–4 linkage between HexNAc and the adja- cent hexose. The ring fragment ions 0,2 A 5 , 0,2 A 5 -18 and 2,4 A 5 , and the lack of 0,3 A 5 ,...

Ngày tải lên: 29/03/2014, 09:20