scholarly journals Conformational selectivity and high-affinity binding in the complexation of N-phenyl amides in water by a phenyl extended calix[4]pyrrole

2018 ◽  
Vol 9 (36) ◽  
pp. 7186-7192 ◽  
Author(s):  
L. Escobar ◽  
A. Díaz-Moscoso ◽  
P. Ballester
Keyword(s):  
Binding Affinity ◽  
Affinity Binding ◽  
High Affinity Binding ◽  
High Affinity ◽  
High Binding ◽  
High Binding Affinity

We report the synthesis of a tetrapyridinium phenyl extended calix[4]pyrrole receptor that shows high binding affinity and selectivity for the complexation of the cis-conformers of N-phenyl amides in water.

High-affinity binding of folate to a serum protein in chronic myelogenous leukemia: effect of binder concentration, pH, and temperature.

1981 ◽  
Vol 27 (2) ◽  
pp. 316-318
Author(s):  
J Holm ◽  
S I Hansen ◽  
J Lyngbye
Keyword(s):  
Binding Affinity ◽  
Chronic Myelogenous Leukemia ◽  
Equilibrium Dialysis ◽  
Exchange Chromatography ◽  
Myelogenous Leukemia ◽  
Affinity Binding ◽  
High Affinity Binding ◽  
High Affinity ◽  
Positive Cooperativity ◽  
Binding Type

Abstract Serum from a patient with chronic myelogenous leukemia was subjected to anion-exchange chromatography on DEAE-Sepharose CL-6B. High-affinity binding of [3H]folate to front effluent, eluted at a low salt gradient, was studied in equilibrium-dialysis experiments (37 degrees C, pH 7.4). As suggested by the data, folate binding displayed positive cooperativity. Dilution of the binder solution resulted in a shift to a simple non-cooperative binding type and increased binding affinity. Furthermore, binding was inhibited at pH 5.0 and at low temperature (7 degrees C). This study demonstrates important similarities between high-affinity folate binding in milk and serum: positive cooperativity and dependence of binding affinity on concentration of binder. Identical mechanisms may underly these phenomena in milk and serum. The apparent relationship between binding type and concentration of binder shown herein seems to agree fairly well with recent observations on sera from groups of healthy persons.

scholarly journals Cyclic peptide unguisin A is an anion receptor with high affinity for phosphate and pyrophosphate

2017 ◽  
Vol 15 (14) ◽  
pp. 2962-2967 ◽  
Author(s):  
A. Daryl Ariawan ◽  
James E. A. Webb ◽  
Ethan N. W. Howe ◽  
Philip A. Gale ◽  
Pall Thordarson ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Cyclic Peptide ◽  
Anion Receptor ◽  
High Affinity ◽  
High Binding ◽  
Cyclic Heptapeptide ◽  
High Binding Affinity

Unguisin A (1) is a marine-derived, GABA-containing cyclic heptapeptide with a high binding affinity for phosphates.

Characteristics of high-affinity folate binding in human leukocytes.

1983 ◽  
Vol 29 (5) ◽  
pp. 869-870 ◽  
Author(s):  
J Holm ◽  
S I Hansen ◽  
J Lyngbye
Keyword(s):  
Ligand Binding ◽  
Binding Affinity ◽  
Binding Protein ◽  
Equilibrium Dialysis ◽  
Normal Subjects ◽  
Affinity Binding ◽  
High Affinity Binding ◽  
Human Leukocytes ◽  
High Affinity ◽  
Positive Cooperativity

Abstract High-affinity binding of [3H]folate in leukocytes from normal subjects was studied in equilibrium dialysis experiments (pH 7.4, 37 degrees C). Binding displayed positive cooperativity, and the binding affinity increased with decreasing concentration of the binding protein. Both phenomena could be interpreted in terms of ligand binding to a polymerizing system where the affinity of ligand for the oligomer is greater than its affinity for the polymer prevailing at higher concentrations of the binding protein.

A “clicked” porphyrin cage with high binding affinity towards fullerenes

RSC Advances ◽  
2014 ◽  
Vol 4 (52) ◽  
pp. 27389-27392 ◽  
Author(s):  
Jianhong Zhang ◽  
Xiaoyan Zheng ◽  
Runsheng Jiang ◽  
Yanwen Yu ◽  
Yongjun Li ◽  
...  
Keyword(s):  
Binding Affinity ◽  
High Affinity ◽  
High Binding ◽  
High Binding Affinity

A cage-structured receptor synthesized via a facile “click” approach is easy to synthesize and modify and shows high affinity for fullerenes.

Characterization of a Mode of Specific Binding of Fibrin Monomer through its Amino-Terminal Domain by Macrophages and Macrophage Cell-Lines

1990 ◽  
Vol 63 (02) ◽  
pp. 193-203 ◽  
Author(s):  
John R Shainoff ◽  
Deborah J Stearns ◽  
Patricia M DiBello ◽  
Youko Hishikawa-Itoh
Keyword(s):  
Peritoneal Macrophages ◽  
Affinity Binding ◽  
Macrophage Cell ◽  
High Affinity Binding ◽  
Amino Terminal ◽  
High Affinity ◽  
Terminal Domain ◽  
Weak Binding ◽  
Amino Terminal Domain

SummaryThe studies reported here probe the existence of a receptor-mediated mode of fibrin-binding by macrophages that is associated with the chemical change underlying the fibrinogen-fibrin conversion (the release of fibrinopeptides from the amino-terminal domain) without depending on fibrin-aggregation. The question is pursued by 1) characterization of binding in relation to fibrinopeptide content of both the intact protein and the CNBr-fragment comprising the amino-terminal domain known as the NDSK of the protein, 2) tests of competition for binding sites, and 3) photo-affinity labeling of macrophage surface proteins. The binding of intact monomers of types lacking either fibrinopeptide A alone (α-fibrin) or both fibrinopeptides A and B (αβ-fibrin) by peritoneal macrophages is characterized as proceeding through both a fibrin-specific low density/high affinity (BMAX ≃ 200–800 molecules/cell, KD ≃ 10−12 M) interaction that is not duplicated with fibrinogen, and a non-specific high density/low affinity (BMAX ≥ 105 molecules/cell, KD ≥ 10−6 M) interaction equivalent to the weak binding of fibrinogen. Similar binding characteristics are displayed by monocyte/macrophage cell lines (J774A.1 and U937) as well as peritoneal macrophages towards the NDSK preparations of these proteins, except for a slightly weaker (KD ≃ 10−10 M) high-affinity binding. The high affinity binding of intact monomer is inhibitable by fibrin-NDSK, but not fibrinogen-NDSK. This binding appears principally dependent on release of fibrinopeptide-A, because a species of fibrin (β-fibrin) lacking fibrinopeptide-B alone undergoes only weak binding similar to that of fibrinogen. Synthetic Gly-Pro-Arg and Gly-His-Arg-Pro corresponding to the N-termini of to the α- and the β-chains of fibrin both inhibit the high affinity binding of the fibrin-NDSKs, and the cell-adhesion peptide Arg-Gly-Asp does not. Photoaffinity-labeling experiments indicate that polypeptides with elec-trophoretically estimated masses of 124 and 187 kDa are the principal membrane components associated with specifically bound fibrin-NDSK. The binding could not be up-regulated with either phorbol myristyl acetate, interferon gamma or ADP, but was abolished by EDTA and by lipopolysaccharide. Because of the low BMAX, it is suggested that the high-affinity mode of binding characterized here would be too limited to function by itself in scavenging much fibrin, but may act cooperatively with other, less limited modes of fibrin binding.

High Affinity Binding Sites for Activated Protein C and Protein C on Cultured Human Umbilical Vein Endothelial Cells

1994 ◽  
Vol 72 (03) ◽  
pp. 465-474 ◽  
Author(s):  
Neelesh Bangalore ◽  
William N Drohan ◽  
Carolyn L Orthner
Keyword(s):  
Binding Sites ◽  
Protein C ◽  
Umbilical Vein ◽  
Activated Protein C ◽  
Affinity Binding ◽  
Cell Binding ◽  
High Affinity Binding ◽  
High Affinity ◽  
Gla Domain ◽  
Umbilical Vein Endothelial Cells

SummaryActivated protein C (APC) is an antithrombotic serine proteinase having anticoagulant, profibrinolytic and anti-inflammatory activities. Despite its potential clinical utility, relatively little is known about its clearance mechanisms. In the present study we have characterized the interaction of APC and its active site blocked forms with human umbilical vein endothelial cells (HUVEC). At 4° C 125I-APC bound to HUVEC in a specific, time dependent, saturable and reversible manner. Scatchard analysis of the binding isotherm demonstrated a Kd value of 6.8 nM and total number of binding sites per cell of 359,000. Similar binding isotherms were obtained using radiolabeled protein C (PC) zymogen as well as D-phe-pro-arg-chloromethylketone (PPACK) inhibited APC indicating that a functional active site was not required. Competition studies showed that the binding of APC, PPACK-APC and PC were mutually exclusive suggesting that they bound to the same site(s). Proteolytic removal of the N-terminal γ-carboxyglutamic acid (gla) domain of PC abolished its ability to compete indicating that the gla-domain was essential for cell binding. Surprisingly, APC binding to these cells appeared to be independent of protein S, a cofactor of APC generally thought to be required for its high affinity binding to cell surfaces. The identity of the cell binding site(s), for the most part, appeared to be distinct from other known APC ligands which are associated with cell membranes or extracellular matrix including phospholipid, thrombomodulin, factor V, plasminogen activator inhibitor type 1 (PAI-1) and heparin. Pretreatment of HUVEC with antifactor VIII antibody caused partial inhibition of 125I-APC binding indicating that factor VIII or a homolog accounted for ∼30% of APC binding. Studies of the properties of surface bound 125I-APC or 125I-PC and their fate at 4°C compared to 37 °C were consistent with association of ∼25% of the initially bound radioligand with an endocytic receptor. However, most of the radioligand appeared not to be bound to an endocytic receptor and dissociated rapidly at 37° C in an intact and functional state. These data indicate the presence of specific, high affinity binding sites for APC and PC on the surface of HUVEC. While a minor proportion of binding sites may be involved in endocytosis, the identity and function of the major proportion is presently unknown. It is speculated that this putative receptor may be a further mechanisms of localizing the PC antithrombotic system to the vascular endothelium.

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