Colorimetric Studies on the Interaction of Quinhydrone with Monosodium Glutamate (MSG) in Aqueous Medium

2021 ◽  
Vol 14 (3) ◽  
pp. 5457-5461
Author(s):  
Ramesh T N ◽  
Sharath S V
Keyword(s):  
Aqueous Medium ◽  
Monosodium Glutamate ◽  
Colorimetric Method ◽  
Acid Group ◽  
Hydroxyl Group ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
Carboxylic Acid Group ◽  
Amino Carboxylic Acid ◽  
Ph Conditions

The interaction of quinhydrone with monosodium glutamate (MSG) in aqueous medium has been investigated using colorimetric method at different pH conditions. Quinhydrone is a mixture of quinone and hydroquinone. In acidic pH, hydroquinone is dominating and the hydroxyl group of hydroquinone interacts with the amino/carboxylic acid group of glutamate ion due to hydrogen bonds thus influences the solution. While in alkaline pH, the colour of the quinhydrone is brown due to benzoquinone being dominating component and can interact with amino group of glutamate ion thus resulting in the formation of di-anilido-quinone. This will lead to an increase of intensity of quinhydrone solution. Glutamate being amphoteric in nature, provides an option to examine it in both acidic and alkaline pH. The effectiveness of detection of MSG in alkaline medium is better due to its favourable interactions.

scholarly journals Critical Design Features of Phenyl Carboxylate-Containing Polymer Microbicides

2006 ◽  
Vol 50 (9) ◽  
pp. 3081-3089 ◽  
Author(s):  
Robert F. Rando ◽  
Sakae Obara ◽  
Mark C. Osterling ◽  
Marie Mankowski ◽  
Shendra R. Miller ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Mononuclear Cells ◽  
Hydroxypropyl Methylcellulose ◽  
Acid Group ◽  
Carboxylic Acid Group ◽  
Peripheral Blood Mononuclear ◽  
Immunodeficiency Virus ◽  
Ph Conditions ◽  
The Difference

ABSTRACT Recent studies of cellulose-based polymers substituted with carboxylic acids like cellulose acetate phthalate (CAP) have demonstrated the utility of using carboxylic acid groups instead of the more common sulfate or sulfonate moieties. However, the pKa of the free carboxylic acid group is very important and needs careful selection. In a polymer like CAP the pKa is approximately 5.28. This means that under the low pH conditions found in the vaginal lumen, CAP would be only minimally soluble and the carboxylic acid would not be fully dissociated. These issues can be overcome by substitution of the cellulose backbone with a moiety whose free carboxylic acid group(s) has a lower pKa. Hydroxypropyl methylcellulose trimellitate (HPMCT) is structurally similar to CAP; however, its free carboxylic acids have pKas of 3.84 and 5.2. HPMCT, therefore, remains soluble and molecularly dispersed at a much lower pH than CAP. In this study, we measured the difference in solubility and dissociation between CAP and HPMCT and the effect these parameters might have on antiviral efficacy. Further experiments revealed that the degree of acid substitution of the cellulose backbone can significantly impact the overall efficacy of the polymer, thereby demonstrating the need to optimize any prospective polymer microbicide with respect to pH considerations and the degree of acid substitution. In addition, we have found HPMCT to be a potent inhibitor of CXCR4, CCR5, and dual tropic strains of human immunodeficiency virus in peripheral blood mononuclear cells. Therefore, the data presented herein strongly support further evaluation of an optimized HPMCT variant as a candidate microbicide.

Comparative performance of flame retardancy, physiological comfort, and durability of cotton textiles treated with alkaline and acidic casein suspension

2017 ◽  
Vol 48 (6) ◽  
pp. 969-991 ◽  
Author(s):  
Sajid Faheem ◽  
Vijay Baheti ◽  
Maros Tunak ◽  
Jakub Wiener ◽  
Jiri Militky
Keyword(s):  
Flame Retardant ◽  
Burning Rate ◽  
Flame Retardancy ◽  
Cotton Fabrics ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
Comparative Performance ◽  
Water Washing ◽  
Increase With Increase ◽  
Ph Conditions

The objective of the present study was to investigate the effect of coating of different concentrations and pH of aqueous casein suspension on thermo-oxidative properties, flame retardant behavior as well as physiological comfort of cotton fabrics. The flame retardant behavior was found to increase with increase in concentration of casein suspension in both alkaline and acidic pH conditions. The burning rate of 2.1 mm/s and 2.4 mm/s was measured for the samples of 150 g/L casein suspensions in acidic and alkaline pH, respectively. Moreover, better thermo-oxidative properties were obtained for the samples of casein suspension prepared in acidic pH than alkaline pH. The 150 g/L casein produced 19% and 28% residue, respectively for alkaline and acidic suspensions at 600℃. Furthermore, the phenomenon of intumescence was largely observed in case of samples coated with acidic casein suspension due to easier release of ammonia from protonated casein. These samples further exhibited relatively better durability against water washing and UV ageing as compared to those treated with alkaline casein suspension, however delivered poor physiological comfort properties due to blockage of fabric porosity by higher viscosity of casein in acidic pH.

Two modes of phosphate transport by turtle urinary bladder

1980 ◽  
Vol 238 (1) ◽  
pp. F31-F36 ◽  
Author(s):  
J. P. Johnson ◽  
S. Green ◽  
J. H. Schwartz
Keyword(s):  
Urinary Bladder ◽  
Phosphate Transport ◽  
Phosphate Concentration ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
The Difference

The effects of changes in pH and addition of CO2/HCO3- on transepithelial phosphate transport were studied in turtle urinary bladder. Net mucosa-to-serosa flux of phosphate (JP) was determined as the difference between unidirectional 32P fluxes in the absence of transepithelial electrochemical gradients. With 5 mM phosphate in HCO3--free Ringer at pH 8.4, JP was 21.8 +/- 7.4 nmol . 8 cm-2 . h-1. There was a slight increase in JP with isohydric addition of 10 mM HCO3-. Addition of 5% CO2, which reduced pH to 7.3, did not affect JP. At pH 8.4, JP was not affected by ouabain or dinitrophenol and increased progressively as phosphate concentration was raised between 0.5 and 10 mM. At pH 6.2 in the absence of exogenous CO2 and HCO3-, JP was undectable. With 2.5 mM HCO3- and 5% CO2 at pH 6.5, JP was 61.3 +/- 16.0 and decreased to 30.6 +/- 1.6 nmol . 8 cm-2 . h-1 when pH was raised to 7.2 by increasing HCO3- to 10 mM. At pH 6.5 JP was inhibited by both ouabain and dinitrophenol. These results suggest that at acidic pH, JP results from the tranport of H2PO4-. The transport of H2PO4- is CO2 dependent and inhibited by ouabain and dinitrophenol. In contrast, at alkaline pH, JP results from the transport of HPO4(2-), which is neither CO2 dependent nor inhibited by ouabain or dinitrophenol.

scholarly journals Heterocyclic boronic acids display sialic acid selective binding in a hypoxic tumor relevant acidic environment

2017 ◽  
Vol 8 (9) ◽  
pp. 6165-6170 ◽  
Author(s):  
A. Matsumoto ◽  
A. J. Stephenson-Brown ◽  
T. Khan ◽  
T. Miyazawa ◽  
H. Cabral ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Boronic Acids ◽  
Sialic Acids ◽  
Strong Interactions ◽  
Acidic Ph ◽  
Acidic Environment ◽  
Selective Binding ◽  
High Affinity ◽  
Ph Conditions ◽  
Hypoxic Tumor

A group of heterocyclic boronic acids demonstrating unusually high affinity and selectivity for sialic acids are described, with strong interactions under the weakly acidic pH conditions associated with a hypoxic tumoral microenvironment.

The inner salt 4-carboxy-2-(pyridinium-4-yl)-1H-imidazole-5-carboxylate monohydrate

2006 ◽  
Vol 62 (7) ◽  
pp. o2751-o2752 ◽  
Author(s):  
Ting Sun ◽  
Jian-Ping Ma ◽  
Ru-Qi Huang ◽  
Yu-Bin Dong
Keyword(s):  
Carboxylic Acid ◽  
Dihedral Angle ◽  
Title Compound ◽  
Acid Group ◽  
Planar Structure ◽  
Carboxyl Group ◽  
Carboxylic Acid Group ◽  
Pyridyl Group ◽  
Compound C

In the title compound, C10H7N3O4·H2O, one carboxyl group is deprotonated and the pyridyl group is protonated. The inner salt molecule has a planar structure, apart from the carboxylic acid group, which is tilted from the imidazole plane by a small dihedral angle of 7.3 (3)°.

The significance of the Cα substituent in the selective inhibition of matrix metalloproteinases 1 and 9

2011 ◽  
Vol 392 (11) ◽  
Author(s):  
Riyad Domingo ◽  
Kelly Chibale ◽  
Edward D. Sturrock
Keyword(s):  
Hydrogen Bonding ◽  
Matrix Metalloproteinases ◽  
Active Sites ◽  
Unsaturated Compound ◽  
Selective Inhibition ◽  
Acid Group ◽  
Side Chain ◽  
Carboxylic Acid Group ◽  
Lead Compounds ◽  
Hydrogen Bonding Interactions

Abstract Matrix metalloproteinases (MMPs) cleave and degrade most components of the extracellular matrix, and unregulated MMP activity has been correlated to cancer and metastasis. Hence there is a burgeoning need to develop inhibitors that bind selectively to structurally similar MMPs. The inhibition profiles of peptidomimetics containing Cα substituents at the α,β unsaturated carbon were evaluated against the recombinant forms of ADAM17, MMP1, and MMP9. The dicarboxylic acid D2 and hydroxamate C2 inhibited MMP9 but not MMP1. The unsaturated compound E2 displayed selective inhibition for MMP1, compared with the saturated precursor C2, with an IC50 value of 3.91 μm. The molecular basis for this selectivity was further investigated by the molecular docking of E2 and D2 into the active sites of MMP1 and MMP9. These data demonstrate hydrogen-bonding interactions between the carbonyl group of the Cα substituent of E2 and the side chain of Asn180 present in the active site of MMP1. Conversely, the docked MMP9-D2 structure shows hydrophobic and hydrogen bonding between the ligand’s morpholine substituent and second carboxylic acid group with Leu187 and an amide, respectively. This study suggests that substituents other than P1′ and P2′ may confer selectivity among MMPs and may aid in the search for novel lead compounds.

Bioerodible Polypyrrole

2001 ◽  
Vol 711 ◽  
Author(s):  
Alexander Zelikin ◽  
Venkatram Shastri ◽  
David Lynn ◽  
Jian Farhadi ◽  
Ivan Martin ◽  
...  
Keyword(s):  
Erosion Rate ◽  
Acid Group ◽  
The Novel ◽  
Carboxylic Acid Group ◽  
Polymer Backbone ◽  
Cellular Processes ◽  
Novel Approach ◽  
Efficient Control ◽  
And Function ◽  
Substrate Independent

ABSTRACTConductive polymers such as polypyrrole (Ppy) are potentially useful as an active interface for altering cellular processes and function. Their utilization in medically related applications however have been substantially held back by their non-degradable nature. Herein we report a novel approach to creation of bioerodible polypyrroles via modification of pyrrole beta-carbon with an ionizable moiety. It has been shown that the erosion rate of acid-bearing derivative of polypyrrole increases with pH, which is consistent with the pH dependent ionization of carboxylic acid group. The novel paradigm proposed for the creation of bioerodible polypyrroles allows for simple and efficient control over the erosion rate of the substrate independent of the polymer chain length, via the choice of the terminal ionizable group and its concentration along the polymer backbone.

scholarly journals High Summertime Aerosol Organic Functional Group Concentrations from Marine and Seabird Sources at Ross Island, Antarctica, during AWARE

2018 ◽  
Author(s):  
Jun Liu ◽  
Jeramy Dedrick ◽  
Lynn M. Russell ◽  
Gunnar I. Senum ◽  
Janek Uin ◽  
...  
Keyword(s):  
Cloud Condensation Nuclei ◽  
Austral Summer ◽  
Acid Group ◽  
Hydroxyl Group ◽  
Anthropogenic Emissions ◽  
Natural Factor ◽  
Natural Sources ◽  
Organic Composition ◽  
West Antarctic ◽  
The Fourier Transform

Abstract. From November 2015 to December 2016, the ARM West Antarctic Radiation Experiment (AWARE) measured submicron aerosol properties near McMurdo Station at the southern tip of the Ross Island. Submicron organic mass (OM), particle number, and cloud condensation nuclei concentrations were higher in summer than other seasons. The measurements included a range of compositions and concentrations that likely reflected both local anthropogenic emissions and natural background sources. We isolated the natural organic components by separating a natural factor and a local combustion factor. The natural OM was 150 times higher in summer than in winter. The local anthropogenic emissions were not hygroscopic and had little contribution to the CCN concentrations. Natural sources that included marine sea spray and seabird emissions contributed 56 % of OM in the austral summer but only 3 % in the austral winter. The natural OM had high hydroxyl group fraction (55 %), 6 % alkane, and 6 % amine group mass, consistent with marine organic composition. In addition, the Fourier transform infrared (FTIR) spectra showed the natural sources of organic aerosol were characterized by amide group absorption, which may be from seabird populations. Carboxylic acid group contributions from natural sources were correlated to incoming solar radiation, indicating that some OM formed by secondary pathways.

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