scholarly journals Identification of a rabbit liver cytosolic binding protein for human growth hormone

1984 ◽  
Vol 221 (3) ◽  
pp. 617-622 ◽  
Author(s):  
S I Ymer ◽  
J L Stevenson ◽  
A C Herington
Keyword(s):  
Growth Hormone ◽  
Binding Affinity ◽  
Binding Protein ◽  
Physiological Role ◽  
Rabbit Liver ◽  
Precipitation Method ◽  
Affinity Column ◽  
Separation Procedure ◽  
Binding Characteristics ◽  
Membrane Bound

A specific growth hormone (GH) binding protein of Mr approx. 100000 has been demonstrated in the cytosolic fraction (200000g supernatant) of pregnant-rabbit liver by gel filtration techniques. This binding species was detectable by a standard charcoal separation procedure but not by the widely used poly(ethylene glycol) precipitation method. The GH binding protein had similar binding characteristics to those of classical membrane-bound GH receptors. The kinetics of association and dissociation, binding affinity (2.56×10(9)1/mol) and hormonal specificity have been established. There appears to be equal or greater amounts of GH binding protein in the cytosol than in the membrane fraction. The presence of the GH binding protein in rabbit liver cytosol was substantiated by its selective purification on a GH-Affigel 15 affinity column. This technique has resulted in a 200-300-fold purification with no substantial change in binding affinity. The ability of a concanavalin A-Sepharose affinity column to also bind the cytosolic binding protein indicates that, like the membrane-bound GH receptor, it is a glycoprotein. This is the first report of a cytosolic binding protein for GH and raises important questions regarding its potential physiological role in the mechanism of action of GH.

scholarly journals Structural studies on membrane-bound and soluble growth-hormone-binding proteins of rabbit liver

1987 ◽  
Vol 242 (3) ◽  
pp. 713-720 ◽  
Author(s):  
S I Ymer ◽  
A C Herington
Keyword(s):  
Growth Hormone ◽  
Liver Cell ◽  
Binding Proteins ◽  
Binding Protein ◽  
Rabbit Liver ◽  
Cross Linking ◽  
Subunit Structure ◽  
Gh Receptor ◽  
Disulphide Bonds ◽  
Binding Subunit

Covalent cross-linking techniques have been used to investigate the structural characteristics of the growth-hormone (GH) receptor in a variety of rabbit liver cell membrane preparations (particulate and soluble). Two classes of GH-binding protein have been identified which differ in their Mr by gel filtration and susceptibility to precipitation with poly(ethylene glycol) (PEG). The first, a PEG-precipitable (Mr approximately 300,000) protein, contained Mr-65,000 and Mr-40,000 binding proteins linked by disulphide bonds. It was present in aqueous extracts derived from microsomal membranes but was not present in cytosol preparations. The second, a PEG-non-precipitable protein (Mr approximately 100,000) was composed of a non-disulphide-linked primary GH-binding subunit of Mr 60,000-66,000. This binding protein was present in all rabbit liver cell fractions and/or preparations. Both binding-protein classes contained intramolecular disulphide bonds. It is not clear whether the Mr-approximately 100,000 form, or perhaps higher-Mr species which have not been identified by cross-linking studies, represents the native, endogenous, form of the GH receptor present in particulate microsomal or plasma membranes. Accordingly, although these data have identified two classes of GH-binding protein, especially a primary GH-binding subunit of Mr 60,000-66,000, they indicate that, unlike studies on the insulin receptor, covalent cross-linking techniques alone are not sufficient to delineate the complete subunit structure of the native and endogenous form of the GH receptor.

scholarly journals Testing and characterizing enzymes and membrane-bound carrier proteins acting on amphipathic ligands in the presence of bilayer membrane material and soluble binding protein. Application to the uptake of oleate into isolated cells

1992 ◽  
Vol 284 (2) ◽  
pp. 353-361 ◽  
Author(s):  
K P M Heirwegh ◽  
J A T P Meuwissen
Keyword(s):  
Binding Site ◽  
Binding Affinity ◽  
Initial Rate ◽  
Binding Protein ◽  
Maximum Velocity ◽  
Water Soluble ◽  
Membrane Material ◽  
Constant Concentration ◽  
Isolated Cells ◽  
Membrane Bound

1. A multiphasic modelling approach [Heirwegh, Meuwissen, Vermeir & De Smedt (1988) Biochem. J. 254, 101-108] is applied to systems containing poorly water-soluble amphipathic reactants, membrane material, soluble binding protein and acceptor protein (enzyme or membrane-bound carrier protein). 2. The field of application is constrained by the assumptions (i) that the amount of acceptor-bound substrate is small compared with the total amount and (ii) that all preceding chemical reactions and steps of mass transport are rapid compared with the chemical change monitored. 3. Initial-rate formulae for systems in which an acceptor interacts with unbound or protein-bound ligand are given. The saturation curves are near-hyperbolic or sigmoidal, depending both (i) on the form of ligand (unbound or protein-bound) acted upon by the acceptor and (ii) on whether the assays are performed at constant concentration of soluble binding protein Cp or at constant substrate/binding-site molar ratio RS. 4. Several diagnostic features permit unequivocal distinction between acceptor action on unbound or protein-bound substrate. In the former case, saturation curves, run at the same constant concentration of one of several binding proteins of increasing binding affinity, will show progressively increasing inhibition, the shape changing from near-hyperbolic at Km′ less than K1′ to sigmoidal at Km′ greater than K1′.Km′ is the effective Michaelis constant of the acceptor and K1′ the effective dissociation constant of the binding sites of the soluble protein (for the sites with the higher binding affinity, if several classes of binding site are present on the protein). Alternatively, the maximum velocity obtained at constant RS less than or equal to 1 should increase hyperbolically with RS/(1-RS) for a binding protein with a single class of binding site. The formula that applies when the binding protein contains two classes of independent binding site is also available. When the acceptor acts on protein-bound ligand, the maximum velocity obtained at constant binding-protein concentration, Cp, increases hyperbolically with Cp. 5. Application of these and additional criteria to initial-rate data on the uptake of oleate into isolated cells supports a mechanism of carrier-mediated uptake of the unbound ligand and allows one to clarify some observations that hitherto had been poorly explained. 6. The influence of soluble binding protein on the reaction and substrate specificities of ligand/acceptor interaction is also discussed. 7. In its present state, data treatment for ‘double binding-protein systems’ generally requires separate determination of the binding parameters of the soluble binding protein.(ABSTRACT TRUNCATED AT 400 WORDS)

Ligand Binding Characteristics and Aggregation Behavior of Purified Cow's Milk Folate Binding Protein Depends on the Presence of Amphiphatic Substances Including Cholesterol, Phospholipids, and Synthetic Detergents

2002 ◽  
Vol 22 (3-4) ◽  
pp. 431-441 ◽  
Author(s):  
Jan Holm ◽  
Steen Ingemann Hansen
Keyword(s):  
Lipid Bilayers ◽  
Binding Protein ◽  
Gel Filtration ◽  
Exchange Chromatography ◽  
Cow’S Milk ◽  
Affinity Column ◽  
Folate Binding Protein ◽  
Binding Characteristics ◽  
Cow's Milk ◽  
Low Concentrations

Folate binding protein was purified from cow's milk by a combination of cation exchange chromatography and methotrexate-AH-sepharose affinity chromatography. Dilution of the preparation to concentrations of protein less than 10 nM resulted in drastic changes of radioligand (folate) binding characteristics, i.e., a decrease in binding affinity with a change from upward to downward convex Scatchard plots and increased ligand dissociation combined with appearance of weak-affinity aggregated forms of the binding protein on gel filtration. These findings, consistent with a model predicting dimerization between unliganded and liganded monomers, were reversed in the presence of material eluted from the affinity column after adsorption of the protein(cofactor) or cholesterol, phospholipids, and synthetic detergents. The latter amphiphatic substances form micelles and lipid bilayers which could separate hydrophobic unliganded monomers from hydrophilic liganded monomers in the surrounding aqueous medium and thereby prevent association between these monomeric forms prevailing at low concentrations of the protein. Our data have some bearings on studies which show that cholesterol and phospholipids are necessary for the clustering of folate receptors in the cell membrane; a process required for optimum receptor function and internalization of folate.

Effect of human growth hormone (GH)-binding protein in human serum on GH binding to rabbit liver membranes

Metabolism ◽  
1992 ◽  
Vol 41 (7) ◽  
pp. 732-737 ◽  
Author(s):  
Tamar Amit ◽  
Ronnie J. Barkey ◽  
Moussa B.H. Youdim ◽  
Zeev Hochberg
Keyword(s):  
Growth Hormone ◽  
Human Serum ◽  
Human Growth Hormone ◽  
Binding Protein ◽  
Human Growth ◽  
Rabbit Liver ◽  
Liver Membranes

scholarly journals Use of calcium dependence as a means to study the interaction between growth hormones and their binding proteins in rabbit liver

1988 ◽  
Vol 250 (2) ◽  
pp. 533-538 ◽  
Author(s):  
R Barnard ◽  
M J Waters
Keyword(s):  
Growth Hormone ◽  
Binding Proteins ◽  
Specific Binding ◽  
Binding Protein ◽  
Liver Microsomes ◽  
Human Growth ◽  
Rabbit Liver ◽  
Scatchard Analysis ◽  
Calcium Dependence ◽  
High Affinity

The affinity of 22,000-Mr human growth hormone (22 K-hGH) for GH binding proteins in rabbit liver is increased approx. 19-fold by 25 mM-Ca2+. In contrast, ovine growth hormone (oGH) binding is Ca2+-independent up to 10 mM, and decreased by greater Ca2+ concentrations. The 20,000-Mr hGH variant (20K-hGH), lacking residues 32-46, exhibits intermediate behaviour. Without Ca2+ there is a residual 40% of maximum specific binding to liver microsomes, and this increases to 65% with liver cytosolic GH binding proteins. In contrast with 22K-hGH, Scatchard analysis of 20K-hGH binding to liver microsomes produces curvilinear plots in the presence of 25 mM-Ca2+. From these results and inhibition studies with monoclonal antibodies to the GH binding proteins, it is concluded that deletion of the region 32-46 from 22K-hGH has eliminated one component of high-affinity Ca2+-potentiable binding. The Ca2+-mediated increase in Ka for the 22K-hGH-binding protein interaction is consistent with convergence of unit negative charges on the hormone and binding protein towards an intercalated Ca2+ ion. A positive charge in the critical region of nonprimate GHs would render their interactions Ca2+-independent and of lower Ka compared with 22K-hGH. A likely candidate for the negatively charged interactive residue is glutamate-33, since it is unique to human GH and is replaced by a positively charged arginine in non-primate GHs. Its absence in 20K-hGH could explain the altered calcium-dependence of 20K-hGH binding to what is probably the type 2 binding protein [Barnard & Waters (1986) Biochem. J. 237, 885-892]. The Ca2+-dependence of 20K-hGH binding to a subset of GH binding proteins provides both a verification and a mechanistic basis for the proposal [Hughes, Tokuhiro, Simpson & Friesen (1983) Endocrinology (Baltimore) 113, 1904-1906] that 20K-hGH binds with high affinity to only a subset of binding proteins in rabbit liver membranes.

scholarly journals Rabbit liver growth hormone receptor and serum binding protein. Purification, characterization, and sequence.

1988 ◽  
Vol 263 (16) ◽  
pp. 7862-7867 ◽  
Author(s):  
S A Spencer ◽  
R G Hammonds ◽  
W J Henzel ◽  
H Rodriguez ◽  
M J Waters ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Protein Purification ◽  
Hormone Receptor ◽  
Growth Hormone Receptor ◽  
Binding Protein ◽  
Rabbit Liver ◽  
Liver Growth ◽  
Serum Binding Protein

Foetal steroid binding protein in British and Japanese women

1987 ◽  
Vol 114 (4) ◽  
pp. 584-588 ◽  
Author(s):  
M. Jawed Iqbal ◽  
Alastair Forbes ◽  
Mark L. Wilkinson ◽  
John W. Moore ◽  
Roger Williams ◽  
...  
Keyword(s):  
Ovarian Function ◽  
Binding Protein ◽  
Premenopausal Women ◽  
Japanese Women ◽  
Sex Hormone Binding Globulin ◽  
Partial Purification ◽  
Enzyme Linked Immunosorbent Assay ◽  
Binding Characteristics ◽  
Steroid Binding ◽  
Steroid Binding Protein

Abstract. In order to examine the newly-discovered sex-steroid binding protein, foetal steroid binding protein (FSBP) in different populations, its binding characteristics and its level were studied by two-tier column ligand binding assay and enzyme-linked immunosorbent assay (ELISA) respectively. In 10 Japanese premenopausal women, analysis of 5α-dihydrotestosterone (DHT) binding in the Cibacron Blue 3GA-Sepharose 6B portion of the column showed a rising plateau pattern with a mean maximum binding of 31.1 ± 7.41%, whereas of 9 similar British women, 8 displayed unsaturable, non-cooperative binding of 11.6 ± 8.22% (P < 0.01). After partial purification of FSBP in these samples, the protein exhibited saturable binding kinetics, median binding 25 (interquartiles 23–34) and 19 (13–25) nmol DHT/l in Japanese and British women, respectively (P < 0.05). By analyzing FSBP by ELISA in 56 Japanese (45 premenopausal) and 59 British (25 premenopausal) women, higher levels were obtained in the whole Japanese group (P = 0.0016) and in the premenopausal Japanese women (P = 0.018) than in their British counterparts. In both nationalities, FSBP levels were higher in premenopausal women, and there was a significant negative correlation of FSBP with age in both populations, particularly in postmenopausal women. FSBP levels did not correlate with weight, parity, sex hormone binding globulin or albumin levels. The influence of FSBP on free steroid levels remains unclear, but some relationship with ovarian function seems a possibility.

Lack of growth hormone effect on insulin-associated suppression of insulinlike growth factor binding protein 1 in humans

Diabetes ◽  
1990 ◽  
Vol 39 (10) ◽  
pp. 1251-1256 ◽  
Author(s):  
C. A. Conover ◽  
P. C. Butler ◽  
M. Wang ◽  
R. A. Rizza ◽  
P. D. Lee
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Binding Protein ◽  
Factor Binding ◽  
Insulinlike Growth Factor ◽  
Hormone Effect

Diagnostic value of fatty acid-binding protein determination in urologists and nephrologists clinical practice

2020 ◽  
pp. 92-99
Author(s):  
Konstantin R. Galkovich
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Binding Protein ◽  
Binding Protein ◽  
Physiological Role ◽  
Diagnostic Value ◽  
Obstructive Nephropathy ◽  
Malignant Neoplasms ◽  
Early Screening ◽  
Fatty Acid Binding ◽  
Acid Binding Protein

This review summarizes the data on the diagnostic value of determining the fatty acid-binding protein (FABP) in urological and nephrological diseases. A physiological role of this protein in the pathogenesis of malignant neoplasms of the kidney, bladder, and prostate was analyzed. The dynamics of FABP in serum and urine with decreased renal function was studied: this protein is considered as a diagnostic and prognostic marker for chronic kidney disease and acute renal injury. The value of FABP for early screening of patients with obstructive nephropathy was revealed, and its role in predicting the restoration of kidney function was studied: the dynamics of FABP content can characterize the process of graft recovery, determine the need for hemodialysis. In patients with oligozooastenospermia, a reduced content of FABP in the ejaculate was registered, which was probably an adverse sign indicating a violation of male fertility.

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