scholarly journals Spectroscopic studies of the binding of bilirubin by ligandin and aminoazo-dye-binding protein A

1976 ◽  
Vol 157 (1) ◽  
pp. 211-216 ◽  
Author(s):  
E Tipping ◽  
B Ketterer ◽  
L Christodoulides ◽  
G Enderby
Keyword(s):  
Association Constant ◽  
Fluorescence Spectra ◽  
Binding Protein ◽  
Protein A ◽  
Spectroscopic Studies ◽  
Absorption And Fluorescence Spectra ◽  
Quantitative Studies ◽  
Dye Binding ◽  
Cotton Effects ◽  
Unbound Bilirubin

Ligandin and aminoazo-dye-binding protein A both bind bilirubin at a single site. Quantitative studies of the interactions using difference spectrophotometry show that at pH 7.0, protein A binds the tetrapyrrole with an association constant (K) greater than or equal to 2 × 10(7) litre/mol, whereas binding by ligandin is slightly weaker (K = 7 × 10(6) litre/mol) at this pH. The protein-bilirubin complexes give rise to absorption and fluorescence spectra quite different from those of unbound bilirubin and also to large Cotton effects. It appears that on binding to both proteins, the ligand is forced into a rigid twisted configuration in a hydrophobic environment. Ligandin and protein A resemble serum albumin in their interactions with bilirubin.

scholarly journals The interactions of haem with ligandin and aminoazo-dye-binding protein A.

1976 ◽  
Vol 157 (2) ◽  
pp. 461-467 ◽  
Author(s):  
E Tipping ◽  
B Ketterer ◽  
L Christodoulides ◽  
G Enderby
Keyword(s):  
Association Constant ◽  
Protein Complexes ◽  
Binding Protein ◽  
Protein A ◽  
Association Constants ◽  
Dye Binding ◽  
Cotton Effects ◽  
Haem Protein ◽  
Haem Iron ◽  
Soret Region

1. The interactions of ferriprotoporphyrin IX with ligandin and aminoazo-dye-binding protein A result in absorption spectra in the Soret region characteristic of the ligand in its monomeric state. 2. Both proteins are able to bind ferrous as well as ferric haem. 3. Ferriprotoporphyrin IX is bound at a single site on both proteins. At pH7.0, I 0.16M, difference-spectrophotometric measurements gave association constants of 10(7) and 4 × 10(6) LITRE/MOL FOR LIGANDIN AND PROTEin A respectively. Under the same conditions fluorescence-quenching experiments gave an association constant of 2 × 10(7) litre/mol for ligandin. 4. Bilirubin, bromosulphophthalein and oesterone sulphate each compete with haem for binding by the two proteins. 5. Ferriprotoporphyrin IX bound to both ligandin and protein A is able to form co-ordination complexes with CN-, but not, to any measurable extent, with either N3- or F-. From these results it is suggested that binding by the two proteins may not involve the haem iron atom. 6. Both haem-protein complexes give rise to measurable extrinsic Cotton effects in the Soret region. 7. The formation and properties of the ligandin- and protein A-haem complexes are compared with those of haem-albumin, haemoglobin, myoglobin and other haemoproteins.

Spectroscopic Studies of the Energy Levels of the Nd3+ Ion in Single Crystals of SrO.6Al2O3

1988 ◽  
Vol 41 (4) ◽  
pp. 549 ◽  
Author(s):  
H Tajalli
Keyword(s):  
Raman Spectroscopy ◽  
Fluorescence Spectra ◽  
Energy Levels ◽  
Selective Excitation ◽  
Spectroscopic Studies ◽  
Solid State Laser ◽  
Host Lattice ◽  
Absorption And Fluorescence Spectra ◽  
Excitation Spectra ◽  
Laser Material

A detailed study of the polarised absorption and fluorescence spectra and the selective excitation spectra of the Nd3+ ion in the SrO.6Al20 3 host lattice was carried out over the temperature range 4�2 to 500 K. The empirical energy level schemes were determined for two dominant sites of Nd3+ in SrO.6Al20 3 up to 20000 cm -1. The intensity, linewidth and thermal shifts of the transition lines with 4f3 configuration were investigated. The vibrational transitions of Nd3 + : srO.6Al20 3 were also investigated using Raman spectroscopy. The results of the study provide information on the suitability of Nd3+ : srO.6Al20 3 as a solid state laser material.

Spectroscopic properties of the Pr3+ ion in TeO2-WO3-PbO-La2O3 and TeO2-WO3-PbO-Lu2O3 glasses

Open Physics ◽  
2014 ◽  
Vol 12 (1) ◽  
Author(s):  
Bożena Burtan ◽  
Maciej Sitarz ◽  
Radosław Lisiecki ◽  
Witold Ryba-Romanowski ◽  
Piotr Jeleń ◽  
...  
Keyword(s):  
Refractive Index ◽  
Dispersion Relation ◽  
Fluorescence Spectra ◽  
Tellurite Glass ◽  
Spectroscopic Properties ◽  
Spectroscopic Studies ◽  
Luminescence Decay ◽  
Absorption And Fluorescence Spectra ◽  
Ofelt Theory ◽  
Glass Matrices

AbstractThe goal of this work was to investigate the spectroscopic properties of Pr3+ ions, embedded in two different tellurite glass matrices, TeO2-WO3-PbO-La2O3 and TeO2-WO3-PbO-Lu2O3. The absorption and fluorescence spectra have been recorded and analyzed in terms of the Judd-Ofelt theory along with the luminescence decay of the 3P0 and 1D2 levels of the Pr3+ ion. The spectroscopic studies were completed with ellipsometric measurements providing the dispersion relation of the refractive index of the investigated glasses.

scholarly journals Interactions of small molecules with phospholipid bilayers. Binding to egg phosphatidylcholine of some organic anions (bromosulphophthalein, oestrone sulphate, haem and bilirubin) that bind to ligandin and aminoazo-dye-binding protein A

1979 ◽  
Vol 180 (2) ◽  
pp. 327-337 ◽  
Author(s):  
E Tipping ◽  
B Ketterer ◽  
L Christodoulides
Keyword(s):  
Intracellular Transport ◽  
Binding Protein ◽  
Equilibrium Dialysis ◽  
Protein A ◽  
Molar Ratio ◽  
Oestrone Sulphate ◽  
Dye Binding ◽  
Order Of Magnitude ◽  
Saturation Effects ◽  
Limiting Values

1. To assess the possible involvement of ligandin and aminoazo-dye-binding protein A in intracellular transport it is necessary to know how their ligands, most of which are molecules with hydrophobic moieties, interact with cellular membranes. To obtain such information we examined the interactions of bromosulphophthalein, oestrone sulphate, haem and bilirubin with aqueous dispersions of egg phosphatidylcholine and egg phosphatidylchone/cholesterol (1:1, molar ratio) by equilibrium dialysis and spectrophotometry. 2. In all four cases, saturation effects were observed. Values of Vmax (v = mol of compound bound/mol of lipid phosphorus) at 25 degrees C were: for bromosulphophthalein, approximately 0.1; for oestrone sulphate, approximately 0.25; for haem, approximately 0.25 (all at pH 7.4); and for bilirubin 0.1–0.2 (at pH 8.2). 3. Limiting values of v/c (c = unbound concentration) as v leads to 0 at 25 degrees C and pH 7.4 are: for bromosulphophthalein, 6.25 × 10(4) litre-mol-1; for oestrone sulphate, 7.8 × 10(2) litre-mol-1; for haem, 4.5 × 10(5) litre-mol-1; and for bilirubin, approximately 1.2 × 10(4) litre-mol-1. For haem the result depends on the assumption that only the monomeric form binds to the lipid. 4. The binding of each compound was decreased by cholesterol; bromosulphophthalein and oestrone sulphate were affected more than haem and bilirubin. 5. Bromosulphophthalein at saturating concentration decreased the limiting values of v/c of the other three compounds by approximately one order of magnitude. 6. By assuming that the interactions with egg phosphatidylcholine resemble those with the phospholipid components of mammalian intracellular membranes the binding data for phosphyatidylcholine, together with data for binding to the intracellular proteins ligandin and aminoazo-dye-binding protein A, enable the subcellular distributions of the four compounds to be estimated. For the rat hepatocyte up to 92, 51, 98 and 47% of the total bromosulphophthalein, oestrone sulphate, haem and bilirubin respectively may be membrane-bound.

scholarly journals Interactions of small molecules with phospholipid bilayers. Binding to egg phosphatidylcholine of some uncharged molecules (2-acetylaminofluorene, 4-dimethylaminoazobenzene, oestrone and testosterone) that bind to ligandin and aminoazo-dye-binding protein A

1979 ◽  
Vol 180 (2) ◽  
pp. 319-326 ◽  
Author(s):  
Edward Tipping ◽  
Brian Ketterer ◽  
Lucia Christodoulides
Keyword(s):  
Lipid Bilayers ◽  
Partition Coefficients ◽  
Intracellular Transport ◽  
Binding Protein ◽  
Equilibrium Dialysis ◽  
Protein A ◽  
Molar Ratio ◽  
Intracellular Proteins ◽  
Dye Binding ◽  
Membrane Bound

1. To assess the possible involvement of ligandin and aminoazo-dye-binding protein A in intracellular transport it is necessary to know how their ligands, most of which are molecules with hydrophobic moieties, interact with cellular membranes. To obtain such information we have examined the interactions of 2-acetylaminofluorene, 4-dimethylaminoazobenzene, oestrone and testosterone with aqueous dispersions of egg phosphatidylcholine and egg phosphatidylcholine/cholesterol (1:1, molar ratio) by equilibrium dialysis and spectrophotometry. 2. At 25°C and pH7.4, the partition coefficients for binding to phosphatidylcholine [expressed as (mol of ligand bound/mol of phosphatidylcholine)/unbound ligand concentration] were: for 2-acetylaminofluorene, 5.0×103 litre·mol−1; for 4-dimethylaminoazobenzene, 2.1×104 litre·mol−1; for oestrone, 3.1×103 litre·mol−1; and for testosterone, 4.2×102 litre·mol−1. In the ranges studied these values were independent of concentration. The results for the two steroids confirm those of Heap, Symons & Watkins [(1970) Biochim. Biophys. Acta218, 482–495]. 3. The introduction of cholesterol into the lipid bilayers caused large decreases in the partition coefficients of oestrone and testosterone, but had relatively little effect on the binding of 2-acetylaminofluorene and 4-dimethylaminoazobenzene. 4. By assuming that the interactions with egg phosphatidylcholine bilayers resemble those with the phospholipid components of mammalian intracellular membranes the phosphatidylcholine partition coefficients, together with data for binding to the intracellular proteins ligandin and aminoazo-dye-binding protein A, enable the subcellular distributions of the four compounds to be estimated. For the rat hepatocyte up to 98, 99, 89 and 58% of the total 2-acetylaminofluorene, 4-dimethylaminoazobenzene, oestrone and testosterone respectively may be membrane-bound.

Binding of Human Platelet Glycoprotein lb and Actin to Fragments of Actin-Binding Protein

1992 ◽  
Vol 67 (02) ◽  
pp. 252-257 ◽  
Author(s):  
Anne M Aakhus ◽  
J Michael Wilkinson ◽  
Nils Olav Solum
Keyword(s):  
Actin Filaments ◽  
High Speed ◽  
Binding Protein ◽  
Protein A ◽  
Actin Binding ◽  
Platelet Glycoprotein ◽  
Actin Binding Protein ◽  
Crossed Immunoelectrophoresis ◽  
Triton X ◽  
Calpain Inhibitors

SummaryActin-binding protein (ABP) is degraded into fragments of 190 and 90 kDa by calpain. A monoclonal antibody (MAb TI10) against the 90 kDa fragment of ABP coprecipitated with the glycoprotein lb (GP lb) peak observed on crossed immunoelectrophoresis of Triton X-100 extracts of platelets prepared without calpain inhibitors. MAb PM6/317 against the 190 kDa fragment was not coprecipitated with the GP lb peak under such conditions. The 90 kDa fragment was adsorbed on protein A agarose from extracts that had been preincubated with antibodies to GP lb. This supports the idea that the GP Ib-ABP interaction resides in the 90 kDa region of ABP. GP lb was sedimented with the Triton-insoluble actin filaments in trace amounts only, and only after high speed centrifugation (100,000 × g, 3 h). Both the 190 kDa and the 90 kDa fragments of ABP were sedimented with the Triton-insoluble actin filaments.

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