Unesterified Fatty Acids and the Binding of Tryptophan in Human Plasma

1974 ◽  
Vol 47 (5) ◽  
pp. 415-424 ◽  
Author(s):  
G. Curzon ◽  
June Friedel ◽  
Bharati D. Katamaneni ◽  
Monica H. Greenwood ◽  
M. H. Lader
Keyword(s):  
Human Plasma ◽  
Binding Sites ◽  
Binding Constants ◽  
Nefa Concentration ◽  
Plasma Nefa ◽  
Plasma Tryptophan ◽  
Free Tryptophan ◽  
Number Of Binding Sites ◽  
Albumin Molecule

1. The percentage of human plasma tryptophan in the free state (ultrafilterable) was positively and significantly correlated with plasma non-esterified fatty acid (NEFA) concentration. 2. Results obtained either by adding tryptophan to plasma in vitro or from plasma taken during tryptophan infusion indicate one tryptophan binding site per albumin molecule and an inverse relationship between binding constants and NEFA concentration. 3. A single normal subject was atypical as the apparent number of binding sites varied between one and two per albumin molecule (1.54±0.49 sd, four experiments). 4. Spontaneous increases of plasma NEFA during tryptophan infusion were associated with increased free tryptophan. Also addition in vitro of linoleic acid, oleic acid and palmitic acid to plasma caused free tryptophan to increase. 5. The possible significance of NEFA changes on plasma tryptophan binding in various pathological circumstances is discussed.

THE PLATELET “REBOUND-PHENOMENON” DURING PROLONGED, CONTINUOUS PGI2 INFUSION OCCURS AT THE RECEPTOR LEVEL

1987 ◽  
Author(s):  
G Steurer ◽  
H Sinzinger ◽  
P Fitscha
Keyword(s):  
Binding Sites ◽  
Venous Blood ◽  
Intermittent Infusion ◽  
Receptor Level ◽  
Binding Data ◽  
Post Infusion ◽  
Number Of Binding Sites ◽  
Rebound Phenomenon ◽  
Infusion Regimen

During earlier attempts in optimizing the therapeutic regimen with PGI2 we were able to discover an “ intra- and post-infusion platelet rebound” being characterized by an activated platelet function and a diminished responsiveness of platelets to the action of PGI2 in-vitro.In order to verify this phenomenon at the receptor level we infused continuously 6 patients suffering from peripheral vascular disease (PVD) with PGI2 at a rate of 5 ng/kg/min for 5 days. Anticoagulated venous blood has been drawn at different intervals. Saturation binding experiments on platelet membrane fraction have been performed using [3H]iloprost, a stable PGI2 analoque. Analysis of the binding data according to Scatchard demonstrated a decrease of receptor affinity with an increased number of binding sites.It is concluded, that intrainfusion rebound occurs at the receptor level, whereas the postinfusion rebound does not. This is a further piece of evidence that an intermittent infusion regimen is preferable.

scholarly journals Interaction Between α-Glucosidase Inhibitor with Common Blood Proteins: A Thermodynamic and Spectroscopic Studies

2020 ◽  
Vol 32 (7) ◽  
pp. 1756-1762
Author(s):  
K.M. Sachin ◽  
Sameer A. Karpe ◽  
Man Singh ◽  
Ajaya Bhattarai
Keyword(s):  
Circular Dichroism ◽  
Serum Albumin ◽  
Binding Sites ◽  
Binding Constants ◽  
Spectroscopic Studies ◽  
Blood Proteins ◽  
Glucosidase Inhibitors ◽  
Number Of Binding Sites ◽  
Treatment Of Diabetes ◽  
Circular Dichroïsm

The interaction of an α-glucosidase inhibitors class of drug acarbose with globular proteins like bovine serum albumin (BSA), human serum albumin (HSA) and haemoglobin studied by fluorescence, circular dichroism (CD) spectroscopic methods. Acarbose is used for the treatment of diabetes mellitus type 2 and in some countries, prediabetes. The quenching constant (kq) values were calculated by using fluorescence data, higher with haemoglobin (at λext = 405 nm). It indicates the quenching process for the acarbose-haemoglobin interaction. Thus, the binding constants (kb), infers that the electrostatic, hydrogen bonding, and intermolecular interactions play an important role in the proteins, and drug interaction. The number of binding sites (n), between BSA, HSA and haemoglobin with acarbose was estimated by fluorescence data, the highest binding sites (15.55) of acarbose-haemoglobin at (λext = 405nm) indicates that the strong interaction or high quenching interaction. The interactions between BSA, HSA and haemoglobin with acarbose were confirmed by spectroscopic analysis and thermodynamic determination. The circular dichroism (CD) spectra implied the significant change in the conformation of BSA, HSA and haemoglobin upon binding with acarbose.

Temperature Dependent Conformation Changes of Ribulose-1,5-bisphosphate Carboxylase Studied by the Use of 1-Anilino-8-naphthalene Sulfonate

1977 ◽  
Vol 32 (3-4) ◽  
pp. 226-228 ◽  
Author(s):  
Günter F. Wildner ◽  
Jürgen Henkel
Keyword(s):  
Enzyme Activity ◽  
Binding Sites ◽  
Fluorescence Probe ◽  
Fluorescence Emission ◽  
Binding Constants ◽  
Temperature Dependent ◽  
Bisphosphate Carboxylase ◽  
Influence Of Temperature On ◽  
Number Of Binding Sites ◽  
Enzyme Molecules

Abstract The influence of temperature on the structure and enzyme activity of ribulose-1,5-bisphosphate carboxylase, isolated from Euglena gracilis cells, was studied. Freezing of the purified ribulose-1,5-bisphosphate carboxylase preparation causes a severe loss of enzyme activity, which can be restored again by incubation of the enzyme molecules at higher temperatures (50 °C). The titration of both enzyme samples with the fluorescence probe 1-anilino-8-naphthalene sulfonate (ANS) re­vealed an increase of the fluorescence emission of the low temperature form of the enzyme. Two different enzyme conformations can be assumed which differ in the number of binding sites for ANS and Vmax values for the carboxylase reaction but show similar binding constants for ANS and the apparent Km values for C02 .

Synthesis, Characterization of the Mn(II) Complex of Rutin and Interactions between the Complex and Serum Albumins

2012 ◽  
Vol 549 ◽  
pp. 265-268 ◽  
Author(s):  
Hong Xia Li ◽  
Kun Jie Wang ◽  
De Yi Zhang ◽  
Yan Ping Wu ◽  
Hui Xia Feng ◽  
...  
Keyword(s):  
Serum Albumin ◽  
General Formula ◽  
Binding Sites ◽  
Binding Constants ◽  
Fluorescence Method ◽  
Serum Albumins ◽  
Thermogravimetric Analyses ◽  
Number Of Binding Sites

In this work, the complex of rutin-Mn has been synthesized. On the basis of elemental, thermogravimetric analyses, IR, the general formula of this complex, Na3Mn2•L(HCO3)3•3H2O is given. The interaction of serum albumin (BSA and HSA) with this complex has been studied by fluorescence method and the binding constants K (rutin-Mn-BSA: 3.1×108, 8.7×105; rutin-Mn-HSA: 3.3×107, 2.7×105) and the number of binding sites (rutin-Mn-BSA: 1.8, 1.2; rutin-Mn-HSA: 1.6, 1.1) has been obtained.

Effects of hypophysectomy and GH administration on bovine and human GH binding to rat liver membranes

1985 ◽  
Vol 249 (1) ◽  
pp. E56-E62
Author(s):  
J. L. Messina ◽  
S. Eden ◽  
J. L. Kostyo
Keyword(s):  
Binding Sites ◽  
Plasma Membranes ◽  
Specific Binding ◽  
Human Growth ◽  
Male Rats ◽  
Normal Male ◽  
Number Of Binding Sites ◽  
Liver Membranes ◽  
Isolated Liver

Experiments were conducted to investigate the specific binding of highly purified bovine and human growth hormones (bGH and hGH) to purified liver plasma membranes of male rats at various times after hypophysectomy and after the acute intravenous administration of bGH. Liver membranes prepared from hypophysectomized male rats showed a two- to threefold increase in the specific binding of either [125I]iodo-bGH or [125I]iodo-hGH, when compared with membranes prepared from the livers of age-matched normal male rats. The increase in GH binding was apparent within 3 days after hypophysectomy and persisted for a number of weeks after the operation. The increase in GH binding produced by hypophysectomy appeared to be due to an increase in the number of binding sites present on the membranes. The intravenous injection of 200 micrograms of bGH into hypophysectomized male rats 5-60 min before they were killed markedly reduced the ability of liver membranes prepared from these animals to bind [125I]iodo-bGH specifically. This decrease in GH binding seen after the injection of bGH may have been due to the development of a slowly dissociating hormone-binding site complex, which thereby reduced the number of available binding sites. This conclusion is supported by the finding that bGH, which is bound in vitro to isolated liver membranes, dissociates slowly and incompletely in the presence of an excess of unlabeled hormone. Moreover, the degree to which the bound hormone can dissociate appears to depend on the length of time that association is allowed to occur.(ABSTRACT TRUNCATED AT 250 WORDS)

COMPETITIVE BINDING OF FREE AND CONJUGATED OESTROGENS TO PLASMA PROTEINS

1969 ◽  
Vol 44 (2) ◽  
pp. 219-230 ◽  
Author(s):  
ELEONORA P. GIORGI ◽  
P. G. CROSIGNANI
Keyword(s):  
Human Plasma ◽  
Binding Sites ◽  
Plasma Proteins ◽  
Equilibrium Dialysis ◽  
Competitive Binding ◽  
Physiological Significance ◽  
Ovarian Vein ◽  
Oestrone Sulphate ◽  
Graafian Follicle ◽  
Number Of Binding Sites

SUMMARY Human plasma was dialysed against increasing concentrations of [4-14C]oestradiol-17β, [4-14C]oestrone, Na[6,7-3H]oestradiol-17β-glucuronide and Na[6,7-3H]oestrone sulphate. When the oestrogens were dialysed separately, binding to a protein with a limited number of binding sites (probably a globulin) could be shown. At comparable concentrations oestrone sulphate was bound to a greater extent than the free compounds and the glucuronide. When free and conjugated oestrogens were dialysed together a displacement of the conjugates from globulin to albumin was demonstrated. This observation was confirmed by the results of the equilibrium dialysis of plasma of ovarian vein blood obtained from a mare and a donkey after injection of [4-14C]oestradiol-17β and Na[6,7-3H]oestradiol-177β-glucuronide into a Graafian follicle of the homolateral ovary. The possible physiological significance of this competition between free and conjugated oestrogens is discussed.

scholarly journals DNA and BSA Interaction, DNA Cleavage and In Vitro Cytotoxicity of Copper(II) Complexes: [Cu(bba)(phen)](ClO4)2 is Promising Chemotherapeutic Scaffold

2020 ◽  
Vol 12 (1) ◽  
pp. 111-133 ◽  
Author(s):  
J. Manivel ◽  
S. Sangeetha ◽  
M. Murali
Keyword(s):  
Dna Cleavage ◽  
Hydrophobic Interactions ◽  
Binding Constants ◽  
Carcinoma Cells ◽  
Spectral Parameters ◽  
Pyramidal Geometry ◽  
Number Of Binding Sites ◽  
Ct Dna ◽  
Bsa Interaction

Three mononuclear copper(II) complexes of the type [Cu(bba)(bpy/phen/dpa)](ClO4)2 (1-3), where bba (N,N-bis(benzimidazol-2-ylmethyl)amine) and bpy (2,2’-bipyridine, 1) or phen (1,10-phenanthroline, 2) or dpa (2,2’-dipyridylamine, 3), have been isolated. The coordination geometry of 1 around copper(II) is square pyramidal. The electronic absorption (639-667 nm) and EPR spectral parameters (g||, ~2.25; A||, 181-186 × 10-4 cm-1; g||/A||, 122−134 cm)  reveal that 1-3 possesses a square pyramidal geometry with CuN5 chromophore. Different spectral and electrochemical measurements clearly demonstrate partial intercalative interaction of 1-3 to CT DNA. Complexes strongly quench the intrinsic fluorescence of BSA through a static quenching procedure by forming BSA-(1/2/3) adducts, which are stabilized by hydrophobic interactions. The number of binding sites and binding constants were calculated. The energy transfer from BSA to Cu(II) complexes occurs with high probability. Notably, 1-3 exhibit more effective pUC 19 DNA cleavage in the presence of H2O2. Complexes 2 and 1 show remarkable cytotoxicity (IC50: 2, 2.17; 1, 8.33 mM) against human cervical carcinoma cells (HeLa) and more potent than cisplatin (IC50, 16.40 mM) while 3 exhibits less cytotoxicity (IC50, 20.82 mM). The DNA binding propensity, cleavage ability and cytotoxicity follow the order 2>1>3. Interestingly, they are non-toxic to healthy cells.

scholarly journals Effect of oxidized glutathione and temperature on inositol 1,4,5-trisphosphate binding in permeabilized hepatocytes

1995 ◽  
Vol 310 (1) ◽  
pp. 185-192 ◽  
Author(s):  
D C Renard-Rooney ◽  
S K Joseph ◽  
M B Seitz ◽  
A P Thomas
Keyword(s):  
Ligand Binding ◽  
Binding Sites ◽  
Binding Activity ◽  
Oxidized Glutathione ◽  
Ip3 Receptors ◽  
Ip3 Receptor ◽  
Temperature Dependent ◽  
Inositol 1,4,5 Trisphosphate ◽  
Number Of Binding Sites

The effect of oxidized glutathione (GSSG) on inositol 1,4,5-trisphosphate (IP3) binding and the activity of IP3-gated Ca2+ channels was examined in permeabilized hepatocytes. The permeability properties of the channel were measured by using Mn2+ quenching of compartmentalized fura-2 at 37 degrees C and at 4 degrees C for comparison with IP3-binding measurements. GSSG (2 mM) increased the IP3-sensitivity of Mn2+ quenching, consistent with previous studies based on Ca(2+)-release measurements [Renard, Seitz and Thomas (1992) Biochem. J. 284, 507-512]. Measurements of [3H]IP3 binding were made at 4 degrees C after preincubation of permeabilized hepatocytes at 37 degrees C in the absence or presence of GSSG. Under these conditions GSSG stimulated IP3 binding by increasing the number of binding sites without changing the Kd. This effect was observed in the absence or presence of Ca2+, but was abolished when the preincubation with GSSG was carried out at 4 degrees C. Thimerosal also stimulated [3H]IP3 binding, but this effect was mediated both by an increase in the maximum number of binding sites and by a decrease in the Kd. The effects of thimerosal and GSSG were not additive. Further analysis of the effect of GSSG revealed that preincubation of permeabilized hepatocytes at 37 degrees C results in a progressive loss of [3H]IP3-binding sites that can be prevented and reversed by inclusion of GSSG. A parallel loss of IP3-sensitive Mn(2+)-quenchable stores was observed after incubation at 37 degrees C, and this could also be reversed by adding back GSSG. The loss of IP3 binding was not the result of IP3-receptor proteolysis, as judged by Western blotting of immunoreactive protein. The sensitivity of [3H]IP3 binding in permeabilized hepatocytes to varied ratios of GSSG and GSH suggests that the IP3 receptor responds to an oxidized redox environment such as that found in the lumen of the endoplasmic reticulum. GSSG had no direct effect on the ligand-binding activity of detergent-solubilized and partially purified IP3 receptors. We conclude that GSSG exerts an indirect effect on the IP3 receptors in permeabilized hepatocytes by preventing a temperature-dependent loss of IP3-binding sites. We suggest that the hepatic IP3 receptors may interact with a thiol-disulphide oxidoreductase that utilizes GSSG as a substrate and prevents inappropriate unfolding of the ligand-binding domain occurring after incubation of the receptor at 37 degrees C in vitro.

In vitro study of the binding between chlorpyrfos and sex hormones using headspace solid-phase microextraction combined with high-performance liquid chromatography

2015 ◽  
Vol 34 (8) ◽  
pp. 819-827 ◽  
Author(s):  
K Farhadi ◽  
R Tahmasebi ◽  
P Biparva ◽  
R Maleki
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Sex Hormones ◽  
Binding Sites ◽  
Solid Phase Microextraction ◽  
High Performance ◽  
Solid Phase ◽  
Hplc Method ◽  
Number Of Binding Sites

Endocrine-disrupting chemicals are compounds that alter the normal functioning of the endocrine system. Organophosphorus insecticides, as chlorpyrifos (CPS), receive an increasing consideration as potential endocrine disrupters. Physiological estrogens, including estrone (E1), 17β-estradiol (E2), and diethylstilbestrol (DES) fluctuate with life stage, suggesting specific roles for them in biological and disease processes. There has been great interest in whether certain organophosphorus pesticides can affect the risk of breast cancer. An understanding of the interaction processes is the key to describe the fate of CPS in biological media. The objectives of this study were to evaluate total, bound, and freely dissolved amount of CPS in the presence of three estrogenic sex hormones (ESHs). In vitro experiments were conducted utilizing a headspace solid phase microextraction (HS-SPME) combined with high-performance liquid chromatography (HPLC) method. The obtained Scatchard plot based on the proposed SPME-HPLC method was employed to determine CPS-ESHs binding constant and the number of binding sites as well as binding percentage of each hormone to CPS. The number of binding sites per studied hormone molecule was 1.10, 1, and 0.81 for E1, E2, and DES, respectively. The obtained results confirmed that CPS bound to one class of binding sites on sex hormones.

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