THE pH DEPENDENCE OF THE ADSORPTION ISOTHERM AND ABSORPTION SPECTRUM OF METHYL ORANGE BOUND TO HUMAN AND BOVINE SERUM ALBUMIN

1953 ◽  
Vol 31 (8) ◽  
pp. 734-745 ◽  
Author(s):  
J. Ross Colvin
Keyword(s):  
Methyl Orange ◽  
Binding Sites ◽  
Binding Capacity ◽  
Ph Dependence ◽  
Human Albumin ◽  
Electrostatic Repulsion ◽  
Bovine Albumin ◽  
Appreciable Increase ◽  
Protein Molecules ◽  
The Difference

The difference between adsorption isotherms and absorption spectra of methyl orange bound to human and to bovine albumin at pH 6.8, 9.1, and 11.0 has been studied. Exaltation of the spectrum of methyl orange bound to human albumin is not necessarily correlated with total binding capacity. However, above pH 6.8, heterogeneity of the binding sites for methyl orange on human albumin increases so markedly that it is reflected in an appreciable increase in extinction coefficient for the first three or four anions bound. The exaltation is accompanied by an increased −ΔF° of binding. Increase in ionic strength diminishes exaltation, and denaturation of the protein destroys it. These effects were not observed for bovine albumin. Results are interpreted in terms of a limited reversible expansion of the human protein molecules, without unfolding, due to intramolecular, electrostatic repulsion between groups.

Mineralcorticoid receptors along the nephron: [3H]aldosterone binding in rabbit tubules

1981 ◽  
Vol 241 (6) ◽  
pp. F605-F611 ◽  
Author(s):  
A. Doucet ◽  
A. I. Katz
Keyword(s):  
Binding Sites ◽  
Binding Capacity ◽  
Specific Binding ◽  
Rabbit Kidney ◽  
Scatchard Analysis ◽  
Thick Ascending Limb ◽  
Collecting Tubule ◽  
The Difference ◽  
Collecting Tubules ◽  
Cortical Collecting Tubule

To identify the site of mineralocorticoid action along the nephron, we measured the specific binding of [3H]aldosterone to nephron segments microdissected from aldosterone-deficient rabbits. Specific binding was defined as the difference between binding measured in the absence or in the presence of 2,000-fold excess of unlabeled hormone (in 10(-18) mol X cm tubule length-1 +/- SE). High specific binding capacity was found in the branched collecting tubule (108 +/- 4), the cortical collecting tubule (119 +/- 9), and the outer medullary collecting tubule (115 +/- 16), whereas specific binding was negligible in the proximal convoluted tubule (8 +/- 9), pars recta (2 +/- 6), medullary thick ascending limb (4 +/- 6), cortical thick ascending limb (6 +/- 2), and distal convoluted tubule (6 +/- 6). In cortical collecting tubules, Scatchard analysis of the specific [3H]aldosterone binding indicated a dissociation constant (KD) of 2.2 X 10(-9) M and a maximum number of binding sites of 157 X 10(-18) mol X cm tubule length-1. The steroid specificity was assessed from the competition of various steroids for [3H]aldosterone binding sites. Receptors from the cortical collecting tubule revealed the following sequence of affinities: aldosterone greater than DOCA greater than spironolactone greater than dexamethasone greater than 5 alpha-dihydrotestosterone = progesterone = 17 beta-estradiol, indicating that the binding sites in the collecting tubule are mineralocorticoid receptors. These results demonstrate significant [3H]aldosterone binding to receptors of high affinity and mineralocorticoid specificity only in the collecting tubule and suggest that this nephron segment is the target site of mineralocorticoid action in the rabbit kidney.

scholarly journals Purification and Metabolism of Rat Antithrombin III

1977 ◽  
Author(s):  
S. Okuda ◽  
M. Nakagawa ◽  
T. Okada ◽  
K. Sawada ◽  
H. Ijichi
Keyword(s):  
Free Radicals ◽  
Binding Sites ◽  
Antithrombin Iii ◽  
Binding Capacity ◽  
Experimental Results ◽  
Affinity Column ◽  
At Iii ◽  
The Difference ◽  
Rat Tissue ◽  
Sepharose 4B

The previously reported heparin sepharose affinity column has been proved to be reduced in its recovery on the repeated uses because of loose binding of ligand to sepharose. We tried to obtain the better recovery of antithrombin III (AT-III) using four different affinity columns of CNBr activated sepharose 4B, AH-sepharose 4B, CH-sepharose 4B, and Epoxy activated sepharose 6B. 3H-labeled heparin was used to check its binding capacity to sepharose gels. Binding of heparin to gel surface was found to be tight in AH-sepharose 4B, CH-sepharose 4B, and Epoxy activated sepharose 6B because of the difference of the binding sites of heparin free radicals but their recovery and purity of AT-III were poor.According to this experimental results, CNBr activated sepharose 4B was used for the purification of rat tissue AT-III and the metabolism of AT-III was investigated from the stand point of 14C-glycine. incorporation into AT-III fractions. 14C radioactivity in the tissue AT-III fractions were observed immediately after injection and reached to the maximum at 6 hours and appeared to be released into circulating pool in 2 hours after injection.

Synthesis of Polyurethane Dendrimers and Transfer Properties of Dye

2013 ◽  
Vol 457-458 ◽  
pp. 65-71
Author(s):  
Jing Ru Jia
Keyword(s):  
Methyl Orange ◽  
Phase Transfer ◽  
Raw Materials ◽  
Toluene Diisocyanate ◽  
Polymerization Process ◽  
Process Conditions ◽  
Addition Polymerization ◽  
Different Temperatures ◽  
The Difference ◽  
Transfer Properties

The polyfunctional organic compounds 2- hydroxymethyl -1,4- butanediol (trihydric alcohol) and toluene diisocyanate -2, 4- diisocyanate (TDI) were taken as the raw materials in this study. A polyurethane dendrimer was synthesized by utilizing the difference in the reaction activity of two isocyanate groups of TDI at different temperatures. The polymerization process conditions were studied. The addition polymerization of para-position NCO groups occurred at 50 °C, and that of ortho NCO groups occurred at 90 °C. According to the structure of the dendrimer synthesized, methyl orange was used as the guest molecule. Consequently, the aqueous methyl orange showed a phase transfer. With the increase of dendrimer concentration, the transfer rate of methyl orange increased.

Specific binding sites for ovine prolactin in three amphibian cell lines

1985 ◽  
Vol 248 (1) ◽  
pp. C80-C87 ◽  
Author(s):  
M. Dunand ◽  
M. L. Aubert ◽  
J. P. Kraehenbuhl ◽  
B. C. Rossier
Keyword(s):  
Growth Hormone ◽  
Cell Lines ◽  
Binding Sites ◽  
Binding Capacity ◽  
Specific Binding ◽  
Human Growth ◽  
Functional Differentiation ◽  
Water Metabolism ◽  
Ovine Prolactin ◽  
Follicle Stimulating Hormones

Established cell lines (TB-6c and TB-M) obtained by continuous culture of epithelial cells from toad Bufo marinus urinary bladder, which, in culture, maintained a high degree of functional differentiation, exhibited a significant number of high-affinity (KA = 1-2 X 10(10) M-1) binding sites detected both with radioiodinated (125I) ovine prolactin (oPRL) and human growth hormone (hGH). Binding capacity was higher in the case of TB-6c cells (7,573 +/- 581 sites/cell) than with the TB-M cells (1,160 +/- 87). Similarly, binding sites for oPRL were characterized on Xenopus laevis kidney-derived cell line A6. With oPRL used both as tracer and standard, significant cross-reaction was observed with hGH, less with human or rat prolactin (PRL), and none with human chorionic somatomammotropin, bovine growth hormone, and rat luteinizing hormone or follicle-stimulating hormones. B. marinus pituitary extracts completely displaced the binding of 125I-oPRL to toad bladder binding sites. This finding of specific sites for PRL on amphibian bladder and kidney cells confirms that PRL exerts specific biological actions for the control of electrolyte and water metabolism in the amphibians.

scholarly journals An approach based on diffusion to study ligand-macromolecule interaction.

2002 ◽  
Vol 49 (3) ◽  
pp. 703-707 ◽  
Author(s):  
Mohammad R Housaindokht ◽  
Mahmood Bahrololoom ◽  
Shirin Tarighatpoor ◽  
Ali A Mossavi-Movahedi
Keyword(s):  
Methyl Orange ◽  
Diffusion Process ◽  
Binding Constant ◽  
Phosphate Buffer ◽  
Binding Capacity ◽  
Free Ligand ◽  
Hill Equation ◽  
New Approach ◽  
Binding Isotherm ◽  
The Hill

A new approach has been developed to study binding of a ligand to a macromolecule based on the diffusion process. In terms of the Fick's first law, the concentration of free ligand in the presence of a protein can be determined by the measurement of those ligands which are diffused out. This method is applied to the study of binding of methyl-orange to lysozyme in phosphate buffer of pH 6.2, at 30 degrees C. The binding isotherm was determined initially, followed by application of the Hill equation to the data obtained, then binding constant and binding capacity were estimated.

scholarly journals Computational investigation on the role of C-Terminal of human albumin on the dimerization of Aβ1-42 peptide

2020 ◽  
Vol 10 (1) ◽  
pp. 4944-4955 ◽  
Keyword(s):  
Computational Study ◽  
Binding Free Energy ◽  
Conformational Dynamics ◽  
Human Albumin ◽  
Potential Of Mean Force ◽  
Amber Force Field ◽  
Aβ Aggregation ◽  
The Difference ◽  
Dynamics Simulations

Alzheimer’s disease (AD) is characterized by the presence of Amyloid-beta (Aβ) peptide, which has the propensity to fold into β-sheets under stress forming aggregated amyloid plaques. Nowadays many studies have focused on the development of novel, specific therapeutic strategies to slow down Aβ aggregation or control preformed aggregates. Albumin, the most abundant protein in the cerebrospinal fluid, was reported to bind Aβ impeding its aggregation. Recently, it has been reported that C-terminal (CTerm) of Human Albumin binds with Aβ1-42, impairs Aβ aggregation and promotes disassembly of Aβ aggregates protecting neurons. In this computational study, we have investigated the effect of CTerm on the conformational dynamics and the aggregation propensity of Aβ1-42 peptide. We have performed molecular dynamics simulations on the Aβ1-42-Aβ1-42 homodimer and Aβ1-42-CTerm of albumin heterodimer using the AMBER force field ff99SBildn. From the Potential of mean force (PMF) study and Binding free energy (BFE) analysis, we observed the association of Aβ1-42 peptide monomer with itself in the form of homodimer to be stronger than its association with the CTerm in the heterodimer complex. The difference in the number of residues in the Aβ1-42 peptide monomer (42 AAs) and CTerm (35 AAs) may be probable reason for the difference in association between the monomeric units in corresponding homodimer and heterodimer complexes. But even then CTerm shows a significant effect on the dimerization of Aβ1-42 peptide. Our findings therefore suggest that CTerm can be used for the disassembly of Aβ1-42 peptide monomer.

scholarly journals Cortical RORβ is required for layer 4 transcriptional identity and barrel integrity

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Erin A Clark ◽  
Michael Rutlin ◽  
Lucia Capano ◽  
Samuel Aviles ◽  
Jordan R Saadon ◽  
...  
Keyword(s):  
Binding Sites ◽  
Binding Capacity ◽  
Chromatin Accessibility ◽  
Excitatory Input ◽  
Orphan Receptor ◽  
Knock Out ◽  
Putative Target ◽  
Layer 4 ◽  
The Relationship ◽  
Receptor Beta

Retinoic acid-related orphan receptor beta (RORβ) is a transcription factor (TF) and marker of layer 4 (L4) neurons, which are distinctive both in transcriptional identity and the ability to form aggregates such as barrels in rodent somatosensory cortex. However, the relationship between transcriptional identity and L4 cytoarchitecture is largely unknown. We find RORβ is required in the cortex for L4 aggregation into barrels and thalamocortical afferent (TCA) segregation. Interestingly, barrel organization also degrades with age in wildtype mice. Loss of RORβ delays excitatory input and disrupts gene expression and chromatin accessibility, with down-regulation of L4 and up-regulation of L5 genes, suggesting a disruption in cellular specification. Expression and binding site accessibility change for many other TFs, including closure of neurodevelopmental TF binding sites and increased expression and binding capacity of activity-regulated TFs. Lastly, a putative target of RORβ, Thsd7a, is down-regulated without RORβ, and Thsd7a knock-out alone disrupts TCA organization in adult barrels.

Differences in density of Concanavalin A-binding sites due to differences in surface morphology of suspended normal and transformed 3T3 fibroblasts

1975 ◽  
Vol 19 (1) ◽  
pp. 21-32
Author(s):  
J.G. Collard ◽  
J.H. Temmink
Keyword(s):  
Surface Morphology ◽  
Concanavalin A ◽  
Binding Sites ◽  
3T3 Cells ◽  
Con A ◽  
3T3 Fibroblasts ◽  
Transformed Fibroblasts ◽  
Transmission Electron ◽  
The Difference ◽  
Electron Microscopes

Calculations of the density of Concanavalin A (Con A)-binding sites on normal and transformed fibroblasts have, as yet, been based on the unproven assumption that suspended cells are smooth spheres. We studied the surface morphology of suspended normal and transformed fibroblasts with scanning and transmission electron microscopes, and found a large difference in surface morphology between suspended normal and transformed 3T3 cells. When this difference in surface morphology was taken into account, the estimated cell surface area of normal 3T3 cells was approximately seven times larger than that of transformed 3T3 cells. Since equal numbers of 3H-Con A molecules are bound on normal and transformed cells, the density of Con A-binding sites is approximately seven times greater on transformed than on normal 3T3 cells. The difference in density of Con A-binding sites between normal and transformed fibroblasts might be sufficient to explain the difference in agglutination response, as originally suggested by Burger, and may also be the cause of the different degrees of clustering of Con A-binding sites on the plasma membrane of these cells.

Bovine Albumin-Like Protein in Commercial Human Albumin for Clinical Use

Vox Sanguinis ◽  
1990 ◽  
Vol 59 (1) ◽  
pp. 1-5
Author(s):  
T. Murozuka ◽  
M. Moriwaka ◽  
H. Ito ◽  
S. Sekiguchi ◽  
M. Naiki ◽  
...  
Keyword(s):  
Human Albumin ◽  
Clinical Use ◽  
Bovine Albumin
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