scholarly journals The binding of hydrogen ions to an acidic glycoprotein from bovine cortical bone

1967 ◽  
Vol 105 (3) ◽  
pp. 1171-1175 ◽  
Author(s):  
A. R. Peacocke ◽  
P A Williams
Keyword(s):  
Sodium Chloride ◽  
Glutamic Acid ◽  
Titration Curve ◽  
Analytical Data ◽  
Total Content ◽  
Bone Sialoprotein ◽  
Model Systems ◽  
Carboxyl Groups ◽  
Hydrogen Ions ◽  
Titration Curves

The H+ ion dissociation of bone sialoprotein in 0·2m-sodium chloride at 25° was studied. The total content of carboxyl groups available for titration was calculated by comparing the titration curve with the titration curves of three model systems and by the use of analytical data. This comparison showed that 7·0 carboxyl groups/mol. do not participate in the titration, and it is proposed that these are aspartic acid or glutamic acid carboxyl groups present as amides; this is also indicated by titration of the sialoprotein after acid hydrolysis. The titration of carboxyl groups was found to agree well with the Linderstrøm-Lang equation for spherical macroions.

scholarly journals The binding of calcium and yttrium ions to a glycoprotein from bovine cortical bone

1967 ◽  
Vol 105 (3) ◽  
pp. 1177-1185 ◽  
Author(s):  
P A Williams ◽  
A. R. Peacocke
Keyword(s):  
Cortical Bone ◽  
Binding Sites ◽  
Association Constant ◽  
Chondroitin Sulphate ◽  
Bone Sialoprotein ◽  
Carboxyl Groups ◽  
Similar Extent ◽  
Strong Electrostatic Interaction ◽  
Titration Curves ◽  
Number Of Binding Sites

The binding of Ca2+ and Y3+ to an acidic glycoprotein from bovine cortical bone, bone sialoprotein, was determined from the titration curves at I 0·2 in the presence and absence of the cations. The binding of Y3+ was greater than that of Ca2+. The value for the association constant, k, for the interaction with Y3+ increased with pH, from log k 2·93 at pH3·4 to log k 3·50 at pH4·4, and the number of binding sites/mol. increased from 4·6 at pH3·4 to 9·1 at pH4·4. It is proposed that the binding site consists of three carboxyl groups, but it is likely that the binding is a strong electrostatic interaction rather than a co-ordination linkage. A chondroitin sulphate–protein complex also extracted from bovine cortical bone interacted with Y3+ and Ca2+ to a similar extent as did bone sialoprotein. It is suggested that these materials are present in bone at the resting and resorbing surfaces and that they contribute to the deposition of yttrium, americium and plutonium at these sites.

Effect of Food Environment on Staphylococcal Enterotoxin Synthesis: A Review

1983 ◽  
Vol 46 (6) ◽  
pp. 545-555 ◽  
Author(s):  
J. L. SMITH ◽  
R. L. BUCHANAN ◽  
S. A. PALUMBO
Keyword(s):  
Staphylococcus Aureus ◽  
Sodium Chloride ◽  
Carbon Source ◽  
Environmental Factors ◽  
Food Environment ◽  
Inoculum Size ◽  
Model Systems ◽  
Sublethal Stress ◽  
Effect Of Food ◽  
Chloride Water

Effects of various nutritional and environmental factors on growth and enterotoxin synthesis by Staphylococcus aureus in model systems and foods are reviewed. Factors discussed include effects of inoculum size, competing microflora, gaseous atmosphere, carbon source, temperature, pH, sodium chloride, water activity, mineral ions and sublethal stress. Areas where additional research is needed are also discussed.

The Co2 Titration Curve of Mixed Venous Blood

1972 ◽  
Vol 43 (4) ◽  
pp. 553-559 ◽  
Author(s):  
C. T. Kappagoda ◽  
J. B. Stoker ◽  
H. M. Snow ◽  
R. J. Linden
Keyword(s):  
Titration Curve ◽  
Venous Blood ◽  
Mixed Venous Blood ◽  
Ph Values ◽  
Titration Curves ◽  
Mixed Venous

1. Simultaneous CO2 titration curves of arterial and mixed venous blood were determined in both dog and man in vivo. 2. The slopes of the CO2 titration curves of mixed venous blood were significantly less than those of the corresponding arterial curves. 3. The non-respiratory pH values of the CO2 titration curves of mixed venous blood were significantly greater than those of the corresponding arterial curves. 4. The theoretical explanations of these differences have been discussed.

scholarly journals Pyrraline Formation Modulated by Sodium Chloride and Controlled by Encapsulation with Different Coating Materials in the Maillard Reaction

Biomolecules ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 721
Author(s):  
Liang ◽  
Chen ◽  
Yang ◽  
Lai ◽  
Yang ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Maillard Reaction ◽  
Gum Arabic ◽  
Coating Material ◽  
Model Systems ◽  
Simultaneous Increase ◽  
Maize Starch ◽  
Coating Materials ◽  
Normal Maize ◽  
High Amylose

Advanced glycation end products (AGEs), which are present in heat-processed foods, have been associated with several chronic diseases. Sodium chloride (NaCl) modulates the formation of furfurals and acrylamide in the Maillard reaction; however, the effects of NaCl on AGE formation are inconsistent. In this study, we investigated the effects of NaCl on pyrraline formation using glucose-lysine model systems. NaCl, especially at 0.50%, promoted Maillard browning and pyrraline formation, with a simultaneous increase in the 3-deoxyglucosone concentration. To reduce the rate of pyrraline formation, NaCl coated with different gums and starches were used. The results showed that NaCl encapsulation is an effective approach to mitigate pyrraline and 3-deoxyglucosone formation. The content of NaCl in the microparticles were 284 ± 12, 269 ± 6, 258 ± 8, 247 ± 10, 273 ± 16, and 288 ± 15 mg/g (coated with waxy maize starch, normal maize starch, HYLON VII high amylose maize starch, gelatinized resistant starch, xanthan gum, and gum arabic, respectively). The heat resistance of the coating material was negatively correlated with the pyrraline and 3-deoxyglucosone formation, whereas the solubility of the coating material had the opposite results. Coating the material with gum had little effects on the reduction of pyrraline and 3-deoxyglucosone.

The effect of valence and Ionic-strength on the measurement of pH buffer capacity

Soil Research ◽  
1994 ◽  
Vol 32 (5) ◽  
pp. 975 ◽  
Author(s):  
RL Aitken ◽  
PW Moody
Keyword(s):  
Ionic Strength ◽  
Titration Curve ◽  
Buffer Capacity ◽  
Experimental Conditions ◽  
Linear Portion ◽  
Titration Curves ◽  
Addition Rate ◽  
Ph Buffer ◽  
Buffer Capacities ◽  
Linear Regressions

Although the measurement of pH buffer capacity (pHBC) is used to determine lime requirement and acid addition rate in acidification studies, the experimental conditions under which pHBC is determined have not been studied. The effect of valence and ionic strength on the measurement of pHBC was investigated on a range of soils. The effect of the monovalent or divalent accompanying ion was examined by establishing separate titration curves for each of 100 soils by adding incremental amounts of either Ca(OH)2, NaOH, HCl or H2SO4 to soil suspended (1 : 5) in water. Linear regressions were fitted to the linear portion of each titration curve and the slopes of these lines were used as a measure of pHBC. For each soil, the pH buffer capacities were statistically compared. The pHBC determined with Ca(OH)2 was significantly (P = 0.05) greater than that determined with NaOH in 92 soils and, on average (all soils), was 2.2 times the pHBC in NaOH. The effect of ionic strength on pHBC was investigated in each of 20 soils by titrating with HCI in water and suspensions at nominal ionic strengths of 0.006, 0.03 and 0.3 m. In all soils there was a trend for increasing pHBC with increasing ionic strength (I) and, for I < 0.03 m, there was a marked increase in pHBC with increasing I. The results are discussed in relation to the effect of valence and ionic strength on pH buffer capacity mechanisms, and the implications with respect to calculating acidification rates and lime requirements.

Conductimetric titrations of symmetrical aliphatic dicarboxylic acids in solvents pyridine and pyridine–benzene mixtures

1990 ◽  
Vol 68 (3) ◽  
pp. 431-434 ◽  
Author(s):  
Turgut Gündüz ◽  
Esma Kiliç ◽  
Mustafa Tastekin ◽  
Güleren Ozkan
Keyword(s):  
Dielectric Constant ◽  
Hydrogen Bonds ◽  
Titration Curve ◽  
Dicarboxylic Acids ◽  
Dielectric Constants ◽  
Tetrabutylammonium Hydroxide ◽  
End Points ◽  
Titration Curves ◽  
Methylene Groups ◽  
Aliphatic Dicarboxylic Acids

Nine symmetrical aliphatic dicarboxylic acids, namely oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, and sebacic acids, were titrated conductimetrically with tetrabutylammonium hydroxide in pyridine and pyridine–benzene mixtures ((2 + 1), (1 + 1), (1 + 2), (1 + 3), and (1 + 4)). Titration curves of the acids exhibited two distinct and stoichiometric end-points in media of dielectric constants 13.5, 10.0, 8.2, 6.3, 5.3, and 4.7, respectively. The closer investigations of the titration curves revealed that three factors mainly influence the shapes of the titration curves: dielectric constant of the medium, number of the methylene groups in the acid, and formation of hydrogen bonds between several species. As dielectric constant of the medium decreases, conductivity of the medium also decreases at any point in the titration curve. Increase in the number of methylene groups from one to five decreases conductivity of the medium linearly at the first end-points of the acids, from then the conductivity becomes practically constant in acids having five to eight methylene groups in pyridine and pyridine–benzene mixtures of 2 + 1 and 1 + 1 ratios. Keywords: conductimetric titration in pyridine, conductimetric titration in pyridine–benzene mixtures, symmetrical aliphatic dicarboxilic acids.

Sign in / Sign up

Export Citation Format

Share Document