scholarly journals Effect of the binding of bilirubin to either the first class or the second class of binding sites of the human serum albumin molecule on its photochemical reaction

1989 ◽  
Vol 257 (3) ◽  
pp. 711-714 ◽  
Author(s):  
S Onishi ◽  
S Itoh ◽  
K Isobe ◽  
M Ochi ◽  
T Kunikata ◽  
...  
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Binding Sites ◽  
Serum Bilirubin ◽  
Bilirubin Concentration ◽  
Kinetics Of ◽  
Albumin Molecule ◽  
Human Serum Albumin Molecule ◽  
Serum Bilirubin Concentration

The kinetics of the photochemical changes of bilirubin were studied at a constant concentration of bilirubin bound either to the first class or to the second class of binding sites of the human serum albumin molecule. The more the bilirubin binds to the first class of binding sites in the human serum albumin molecule, the more readily geometric photoequilibrium to give (ZE)-bilirubin takes place. The more the bilirubin binds to the second class of binding sites or allosterically transformed binding sites induced by added SDS, the more readily structural photoisomerization, i.e. the formation of (EZ)-cyclobilirubin, takes place. When the serum bilirubin concentration is at low, safe, values bilirubin binds exclusively to the first class of binding sites and serves as an antioxidant [Onishi, Yamakawa & Ogawa (1971) Perinatology 1, 373-379]; at these concentrations human serum albumin protects bilirubin from irreversible photodegradation by only allowing readily reversible geometric photoisomerization. As the serum bilirubin concentration increases to high, and potentially dangerous, values, bilirubin binds to the second class of binding sites, and under these conditions human serum albumin seems to promote the photocyclization of bilirubin. During irradiation human serum albumin seems to act by retaining low, useful, concentrations of bilirubin while facilitating irreversible photoisomerization of excess bilirubin.

scholarly journals Fungicide Tebuconazole Influences the Structure of Human Serum Albumin Molecule

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3190 ◽  
Author(s):  
Katarína Želonková ◽  
Samuel Havadej ◽  
Valéria Verebová ◽  
Beáta Holečková ◽  
Jozef Uličný ◽  
...  
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Fluorescence Spectra ◽  
Spectroscopic Techniques ◽  
Binding Modes ◽  
Conformation Changes ◽  
Relevant Role ◽  
Albumin Molecule ◽  
Human Serum Albumin Molecule

Studies of interactions between pesticides and target mammalian proteins are important steps toward understanding the pesticide′s toxicity. Using calorimetric and spectroscopic methods, the interaction between triazole fungicide tebuconazole and human serum albumin has been investigated. The spectroscopic techniques showed that fluorescence quenching of human serum albumin by tebuconazole was the result of the formation of tebuconazole/human serum albumin complex with the static type as the dominant mechanism. The association constant was found to be 8.51 × 103 L/mol. The thermodynamic parameters were obtained as ΔH = −56.964 kJ/mol, ΔS = −115.98 J/mol·K. The main active interactions forming the tebuconazole/human serum albumin complex were identified as the interplay between hydrogen bonds and/or van der Waals forces, based on thermodynamic experiments. These binding modes were corroborated well by the predictions of molecular modeling. Hydrogen bonding of tebuconazole with Arg222, Ala215 and Ala291 of human serum albumin played a relevant role in binding. The conformation changes in secondary structure were characterized by circular dichroism and 3D fluorescence spectra.

scholarly journals Dansylation of human serum albumin in the study of the primary binding sites of bilirubin and l-tryptophan

1979 ◽  
Vol 181 (1) ◽  
pp. 251-253 ◽  
Author(s):  
C Jacobsen ◽  
J Jacobsen
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Binding Site ◽  
Binding Sites ◽  
Lysine Residue ◽  
Bilirubin Binding ◽  
Albumin Molecule ◽  
Common Cavity

Binding of bilirubin and of L-tryptophan to dansylated albumins was investigated. Dansylation of less than one lysine residue per molecule of albumin did not affect the bilirubin binding, but decreased the L-tryptophan binding, indicating that dansylation had taken place in or near the l-tryptophan-binding site. Native albumin and albumin-bilirubin 1:1 complex showed the same affinity for L-tryptophan. The results indicate that, although L-tryptophan and bilirubin are bound in the same region, perhaps in a common cavity of the albumin molecule, such a cavity is sufficiently large to contain both ligands.

Specific interaction of chalcone-protein: Cardamonin binding site II on the human serum albumin molecule

Biopolymers ◽  
2005 ◽  
Vol 79 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Wenying He ◽  
Ying Li ◽  
Jiaqin Liu ◽  
Zhide Hu ◽  
Xingguo Chen
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Binding Site ◽  
Specific Interaction ◽  
Albumin Molecule ◽  
Human Serum Albumin Molecule

Human serum albumin. A study of the nature of its hydrophobic binding sites

1987 ◽  
Vol 52 (5) ◽  
pp. 1362-1374 ◽  
Author(s):  
Petr Štrop ◽  
František Mikeš ◽  
Marie Havranová ◽  
Václav Žižkovský
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Binding Sites ◽  
Alcohol Concentration ◽  
Bulk Solution ◽  
Alkyl Chains ◽  
Hydrophobic Binding ◽  
Albumin Molecule ◽  
Hydrophobic Areas

Spectroscopic labels and hydrophobic chromatography on two different supports were used to compare the size and accessibility of the hydrophobic binding sites of human serum albumin with the accessibility of non-polar residues on the surface of other globular proteins. The binding of the labels 1-alkyl-4-(3-ethoxy-4-hydroxystyryl)pyridinium bromides (HPB) with alkyl chains of different length was investigated in the ultracentrifuge and by spectrophotometry. n-Butyl (C4-HPB) and decyl (C10-HPB) labels bind to albumin with association constants of 8 . 103 and 4 . 104, respectively, at pH 5·50, and with constant of 2·6 . 105 for the C10-HPB label at pH 9·2. Whereas C4-HPB interacts with the site of local polarity of albumin not different from the bulk solution, both the C10-HPB and C16-HPB on the other hand bind to hydrophobic sites, where the solvation of the chromophore is largely reduced as evidenced by the 46 nm shift to higher wavelengths in its spectrum. For other proteins the shift was less then 5 nm. Ten molecules of C10-HPB and four molecules of C16-HPB can be attached to one molecule of albumin. The changes in the spectrum of the bound label induced by palmitate reveal that these binding sites are essentially the same as those for fatty acids. From chromatographic experiments with labeled albumin at different pH carried out on Octyl-Sepharose and Spheron the conclusion was made that the latter support interacts preferentially with the non-polar side chains on the surface of proteins. The retention and the recovery of albumin and defatted albumin was investigated as a function of salt and alcohol concentration and compared with the same parameters of other proteins. In agreement with the proposed structure of the domains of albumin evidence was obtained that the outer surface of the albumin molecule is at neutral pH predominantly hydrophilic, and that the exceptionally large hydrophobic areas are localized solely in crevices.

Polarographic studies on renaturation of urea-denatured human serum albumin

1989 ◽  
Vol 54 (2) ◽  
pp. 536-543 ◽  
Author(s):  
Josef Chmelík ◽  
Pavel Anzenbacher ◽  
Vítěz Kalous
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Irreversible Process ◽  
State Model ◽  
Native Protein ◽  
Main Components ◽  
Two State Model ◽  
Kinetics Of

The renaturation of the two main components of human serum albumin, i.e. of mercaptalbumin and nonmercaptalbumin, was studied polarographically. It has been demonstrated that renaturation of both proteins after 1-min denaturation in 8M urea is reversible. By contrast, renaturation after 200 min denaturation in 8M urea is an irreversible process; the characteristics of renatured mercaptalbumin differ more from the properties of the native protein than the characteristics of nonmercaptalbumin. The studies of the kinetics of renaturation of both proteins have shown that the renaturation can be represented by a two-state model. This means that the existence of stable intermediary products during the renaturation process was not determined polarographically.

Stereoselective kinetics of warfarin binding to human serum albumin: Effect of an allosteric interaction

Chirality ◽  
2002 ◽  
Vol 14 (5) ◽  
pp. 442-448 ◽  
Author(s):  
Ilona Fitos ◽  
J�lia Visy ◽  
Julianna Kardos
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Allosteric Interaction ◽  
Kinetics Of

Zinc–human serum albumin association: testimony of two binding sites

Talanta ◽  
2004 ◽  
Vol 63 (2) ◽  
pp. 503-508 ◽  
Author(s):  
C. André ◽  
Y.C. Guillaume
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Binding Sites
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