scholarly journals Water Electrolysis in Saturated Phosphate Buffer at Neutral pH

ChemSusChem ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5921-5933
Author(s):  
Takahiro Naito ◽  
Tatsuya Shinagawa ◽  
Takeshi Nishimoto ◽  
Kazuhiro Takanabe
Keyword(s):  
Phosphate Buffer ◽  
Water Electrolysis ◽  
Neutral Ph

scholarly journals Cover Feature: Water Electrolysis in Saturated Phosphate Buffer at Neutral pH (ChemSusChem 22/2020)

ChemSusChem ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5775-5775
Author(s):  
Takahiro Naito ◽  
Tatsuya Shinagawa ◽  
Takeshi Nishimoto ◽  
Kazuhiro Takanabe
Keyword(s):  
Phosphate Buffer ◽  
Water Electrolysis ◽  
Neutral Ph

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

scholarly journals Catalysis of Hydrazone and Oxime Peptide Ligation by Arginine

2020 ◽  
Author(s):  
Nathalie Ollivier ◽  
Vangelis Agouridas ◽  
Benoît Snella ◽  
Rémi Desmet ◽  
Hervé Drobecq ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Phosphate Buffer ◽  
Side Chain ◽  
Neutral Ph ◽  
Arginine Hydrochloride ◽  
Guanidinium Group ◽  
Aggregation Inhibitor ◽  
Peptide Ligation

Hydrazone and oxime peptide ligations are catalyzed by arginine. The catalysis is assisted intramolecularly by the side-chain guanidinium group. Hydrazone ligation in the presence of arginine proceeds efficiently in phosphate buffer at neutral pH but is particularly powerful in bicarbonate/CO<sub>2</sub> buffer. In addition to acting as a catalyst, arginine prevents the aggregation of proteins during ligation. With its dual properties as nucleophilic catalyst and protein aggregation inhibitor, arginine hydrochloride is a useful addition to the hydrazone/oxime ligation toolbox.<br>

scholarly journals Catalysis of Hydrazone and Oxime Peptide Ligation by Arginine

2020 ◽  
Author(s):  
Nathalie Ollivier ◽  
Vangelis Agouridas ◽  
Benoît Snella ◽  
Rémi Desmet ◽  
Hervé Drobecq ◽  
...  
Keyword(s):  
Protein Aggregation ◽  
Phosphate Buffer ◽  
Side Chain ◽  
Neutral Ph ◽  
Arginine Hydrochloride ◽  
Guanidinium Group ◽  
Aggregation Inhibitor ◽  
Peptide Ligation

Hydrazone and oxime peptide ligations are catalyzed by arginine. The catalysis is assisted intramolecularly by the side-chain guanidinium group. Hydrazone ligation in the presence of arginine proceeds efficiently in phosphate buffer at neutral pH but is particularly powerful in bicarbonate/CO<sub>2</sub> buffer. In addition to acting as a catalyst, arginine prevents the aggregation of proteins during ligation. With its dual properties as nucleophilic catalyst and protein aggregation inhibitor, arginine hydrochloride is a useful addition to the hydrazone/oxime ligation toolbox.<br>

Bactericidal Effect of Lactoferrin and Its Amidated and Pepsin-Digested Derivatives on Pseudomonasfluorescens: Influence of Environmental and Physiological Factors

2008 ◽  
Vol 71 (12) ◽  
pp. 2468-2474 ◽  
Author(s):  
ANA del OLMO ◽  
PILAR MORALES ◽  
MANUEL NUÑEZ
Keyword(s):  
Complex Systems ◽  
Bactericidal Activity ◽  
Phosphate Buffer ◽  
Bactericidal Effect ◽  
Bovine Lactoferrin ◽  
Medium Ph ◽  
Physiological Factors ◽  
Pepsin Digestion ◽  
Neutral Ph ◽  
Bacterial Inoculum

The influence of environmental and physiological factors such as substrate composition and inoculum characteristics on the bactericidal activity of bovine lactoferrin (LF) and its amidated and pepsin-digested derivatives against Pseudomonasfluorescens was investigated. Amidated LF (AMILF) exerted the most potent bactericidal activity, with a 5.8-log decrease in P.fluorescens counts, and LF the lowest, with just a 1-log decrease, whereas pepsin-digested LF (PDLF) reduced bacterial counts by 2.7 log, after 1 h at 30°C. Amidation of PDLF increased effectiveness by 1.2 log, whereas pepsin digestion of AMILF decreased effectiveness by 2.8 log. Bactericidal activity of LF and its derivatives was higher in Tris buffer than in phosphate buffer. The bactericidal effect of AMILF and PDLF was enhanced as medium pH was increased from 5.5 to 8.5, whereas LF showed higher activity under acidic or basic conditions than at neutral pH. The presence of cations affected the activity of LF and its derivatives, from a concentration of 10 mM for K+, 1 mM for Na+, and 0.1 mM for Ca2+,Co2+,Cu2+, Mg2+,Zn2+, and Fe3+. Bactericidal effectiveness diminished as the bacterial inoculum was increased. Log-phase cultures (10-h incubation) were less sensitive to the bactericidal activity of LF and its derivatives than stationary cultures (20- and 30-h incubation). All these factors should be considered when applications of LF and its derivatives in foods and other complex systems are investigated.

The Synthesis of 6-Aminomethyl-5,6,7,8-Tetrahydropterin

1988 ◽  
Vol 41 (5) ◽  
pp. 667 ◽  
Author(s):  
P Waring
Keyword(s):  
Acid Hydrolysis ◽  
Phosphate Buffer ◽  
Selenium Dioxide ◽  
Tris Buffer ◽  
Side Chain ◽  
Neutral Ph ◽  
Side Chain Loss ◽  
Hydrolysis Of

6-Aminomethyl-5,6,7,8-tetrahydropterin has been prepared by reduction of 2-acetamido-6-cyanopteridin-4(3H)-one* to 2-acetamido-6-aminomethyl- 5,6,7,8-tetrahydropteridin-4(3H)-one followed by acid hydrolysis. The hitherto undescribed 6-cyanopterin was prepared by careful hydrolysis of the 2-acetamido compound prepared by dehydration of the oxime derived from 2-acetamido-6-formylpteridin-4(3H)-one. The latter was prepared by selenium dioxide oxidation of the methyl compound. Oxidation of 6-aminomethyl-5,6,7,8-tetrahydropterin at neutral pH appears to proceed with significant side-chain loss in Tris buffer but not in phosphate buffer.

scholarly journals Michael addition at neutral pH: a facile synthesis of 1,3-dinitroalkanes

2017 ◽  
Vol 95 (12) ◽  
pp. 1261-1266 ◽  
Author(s):  
Porag Bora ◽  
Pranjal P. Bora ◽  
Barisha Wahlang ◽  
Ghanashyam Bez
Keyword(s):  
Organic Compounds ◽  
Michael Addition ◽  
Phosphate Buffer ◽  
Base Catalyst ◽  
Facile Synthesis ◽  
Neutral Ph ◽  
Scalable Synthesis

Base-catalyzed Michael addition of nitroalkane to conjugated nitroalkene suffers serious practical difficulties due to the formation of oligomeric byproduct. Given its importance for synthesis of pharmacologically relevant organic compounds, a scalable synthesis of 1,3-dinitroalkane is developed by addition of nitroalkane to nitroalkene in aqueous phosphate buffer at pH 7.0 with no added traditional base catalyst.

scholarly journals Mercapturic acid formation during the metabolism of arecoline and arecaidine in the rat

1969 ◽  
Vol 113 (1) ◽  
pp. 123-130 ◽  
Author(s):  
E. Boyland ◽  
R. Nery
Keyword(s):  
Spectral Analysis ◽  
Methyl Ester ◽  
Phosphate Buffer ◽  
Nucleophilic Addition ◽  
Synthetic Material ◽  
Large Excess ◽  
Ethanolic Solution ◽  
Pka Values ◽  
First Order ◽  
Neutral Ph

1. In the rat, arecoline is converted into arecaidine and both compounds are converted into N-acetyl-S-(3-carboxy-1-methylpiperid-4-yl) -l-cysteine. 2. The structure of the metabolite was established by (a) synthesis, (b) conversion into N-acetyl-S-(3-methoxycarbonyl-1-methylpiperid-4-yl) -l-cysteine methyl ester, which was chromatographically identical with the synthetic material, and (c) n.m.r.-and i.r.-spectral analysis of the 3-methoxycarbonyl derivative. 3. In ethanolic solution, or in phosphate buffer at pH7·0, arecoline reacted with N-acetyl-l-cysteine to give N-acetyl-S-(3-methoxycarbonyl-1-methylpiperid-4-yl) -l-cysteine; under similar conditions, arecaidine reacted more slowly to give N-acetyl-S-(3-carboxy-1-methylpiperid-4-yl) -l-cysteine. 4. The reaction between arecoline and glutathione or N-acetyl-l-cysteine occurred maximally at neutral pH and decreased rapidly with increasing acidity. At neutral pH, the reactions were bimolecular and second-order when the reactants were in approximately equimolar concentrations and pseudo-unimolecular first-order when arecoline was in large excess. 5. Consideration of the pKa values and degrees of ionization of the reactants and the effect of pH on the stoicheiometry of reaction between arecoline and glutathione or N-acetyl-l-cysteine indicated that reaction between un-ionized species occurred more readily than nucleophilic addition (AdN) reactions involving charged intermediates.

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