At very low concentrations known chaotropes act as kosmotropes for the N and B isoforms of human serum albumin

2013 ◽  
Vol 91 (2) ◽  
pp. 72-78 ◽  
Author(s):  
Priyankar Sen ◽  
Mohd Moin Khan ◽  
Asif Equbal ◽  
Ejaz Ahmad ◽  
Rizwan Hasan Khan
Keyword(s):  
Protein Structure ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Electrostatic Interaction ◽  
Tertiary Structure ◽  
Guanidine Hydrochloride ◽  
Micelle Formation ◽  
Low Concentrations ◽  
Secondary And Tertiary Structure

Very few studies have been done to understand the effect of millimolar concentrations of chaotropes on protein structure. In our previous study we observed that the secondary and tertiary structure of human serum albumin (HSA) increases in the presence of 5 mmol/L urea. Micelle formation in amphoteric detergents increases in the presence of equivalent concentrations of urea. Here, we observed a significant increase in the secondary and tertiary structure of HSA. Interestingly, guanidine hydrochloride, another chaotropic agent, also shows a similar effect. Our results show electrostatic interaction may play a role in neutral to basic transition in HSA. This study further supports the claim that at millimolar concentrations the chaotropes may act as kosmotropes for proteins.

scholarly journals A Comprehensive Spectroscopic Analysis of the Ibuprofen Binding with Human Serum Albumin, Part II

2021 ◽  
Vol 89 (3) ◽  
pp. 30
Author(s):  
Anna Ploch-Jankowska ◽  
Danuta Pentak ◽  
Jacek E. Nycz
Keyword(s):  
Fatty Acids ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Tertiary Structure ◽  
Temperature Characteristic ◽  
The Body ◽  
Structural Modifications ◽  
Influence Of Temperature On ◽  
Exogenous Substances

Human serum albumin (HSA) is the most abundant human plasma protein. HSA plays a crucial role in many binding endos- and exogenous substances, which affects their pharmacological effect. The innovative aspect of the study is not only the interaction of fatted (HSA) and defatted (dHSA) human serum albumin with ibuprofen (IBU), but the analysis of the influence of temperature on the structural modifications of albumin and the interaction between the drug and proteins from the temperature characteristic of near hypothermia (308 K) to the temperature reflecting inflammation in the body (312 K and 314 K). Ibuprofen is a non-steroidal anti-inflammatory drug. IBU is used to relieve acute pain, inflammation, and fever. To determine ibuprofen’s binding site in the tertiary structure of HSA and dHSA, fluorescence spectroscopy was used. On its basis, the fluorescent emissive spectra of albumin (5 × 10−6 mol/dm3) without and with the presence of ibuprofen (1 × 10−5–1 × 10−4 mol/dm3) was recorded. The IBU-HSA complex’s fluorescence was excited by radiation of wavelengths of λex 275 nm and λex 295 nm. Spectrophotometric spectroscopy allowed for recording the absorbance spectra (zero-order and second derivative absorption spectra) of HSA and dHSA under the influence of ibuprofen (1 × 10−4 mol/dm3). To characterize the changes of albumin structure the presence of IBU, circular dichroism was used. The data obtained show that the presence of fatty acids and human serum albumin temperature influences the strength and type of interaction between serum albumin and drug. Ibuprofen binds more strongly to defatted human serum albumin than to albumin in the presence of fatty acids. Additionally, stronger complexes are formed with increasing temperatures. The competitive binding of ibuprofen and fatty acids to albumin may influence the concentration of free drug fraction and thus its therapeutic effect.

Rapid, competitive enzymoimmunoassay for albumin in urine.

1986 ◽  
Vol 32 (4) ◽  
pp. 669-671 ◽  
Author(s):  
J Chesham ◽  
S W Anderton ◽  
C F Kingdon
Keyword(s):  
Diabetic Nephropathy ◽  
Human Serum Albumin ◽  
Horseradish Peroxidase ◽  
Serum Albumin ◽  
Human Serum ◽  
Human Urine ◽  
Solid Phase ◽  
Low Concentrations ◽  
Initiation Of Therapy ◽  
Assay Protocol

Abstract In this solid-phase competitive enzymoimmunoassay for albumin in human urine, antiserum to human serum albumin labeled with horseradish peroxidase (EC 1.11.1.7) is incubated with solid-phase-bound human serum albumin in the presence of sample or standard. Results obtained correlate well (r = 0.96) with those of an established fluoroimmunoassay. The present assay covers the range 0.9 to 200 mg/L and can be performed within 1 h. These characteristics, together with the simplicity of the assay protocol, make it very useful for monitoring low concentrations of albumin in urine. Detection of such minimal albuminuria allows initiation of therapy that may prevent development of clinical proteinuria and associated diabetic nephropathy.

DENATURATION OF HUMAN SERUM ALBUMIN BY CERIUM (III) CHLORIDE

2013 ◽  
Vol 08 (01n02) ◽  
pp. 59-71
Author(s):  
G. REZAEI BEHBAHANI ◽  
M. SHALBAFAN ◽  
N. GHEIBI ◽  
L. BARZEGAR ◽  
H. REZAEI BEHBAHANI ◽  
...  
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Conformational Changes ◽  
Tertiary Structure ◽  
Fluorescence Emission ◽  
Titration Calorimetry ◽  
Tryptophan Residue ◽  
Spectroscopic Methods ◽  
Irreversible Denaturation

Cerium (III) Chloride-induced conformational changes of human serum albumin, HSA, in phosphate buffer, 10 mM at pH 7.4 was investigated, using isothermal titration calorimetry (ITC), UV and fluorescence emission spectroscopic methods. The results indicate that CeCl3, Ce3+, induces irreversible denaturation of the HSA structure. The UV absorption intensity of HSA + Ce3+ shows a slight blueshift in the absorbance wavelength with increasing Ce3+ concentration. The fluorescence intensity was increased regularly and a slight redshift was observed in the emission wavelength. The HSA + Ce3+ complex quenches the fluorescence of HSA and changes the microenvironment of tryptophan residue. The emission intensity increases suggesting the loss of the tertiary structure of HSA. The results obtained from the ITC data are in agreement with the spectroscopic methods. The strong negative cooperativity of Ce3+ binding with HSA (Table 1) recovered from the extended solvation model, indicates that HSA has been denatured as a result of its interaction with Ce3+ ions.

scholarly journals Role of Arg-410 and Tyr-411 in human serum albumin for ligand binding and esterase-like activity

2000 ◽  
Vol 349 (3) ◽  
pp. 813-819 ◽  
Author(s):  
Hiroshi WATANABE ◽  
Sumio TANASE ◽  
Keisuke NAKAJOU ◽  
Toru MARUYAMA ◽  
Ulrich KRAGH-HANSEN ◽  
...  
Keyword(s):  
Human Serum Albumin ◽  
Ligand Binding ◽  
Serum Albumin ◽  
Human Serum ◽  
Aromatic Ring ◽  
Recombinant Proteins ◽  
Expression System ◽  
Guanidine Hydrochloride ◽  
Enzymic Activity ◽  
Phenolic Oxygen

Recombinant wild-type human serum albumin (rHSA), the single-residue mutants R410A, Y411A, Y411S and Y411F and the double mutant R410A/Y411A were produced using a yeast expression system. The recombinant proteins were correctly folded, as they had the same stability towards guanidine hydrochloride and the same CD spectrum as HSA isolated from serum (native HSA). Thus the global structures of the recombinant proteins are probably very similar to that of native HSA. We investigated, by ultrafiltration and CD, the high-affinity binding of two representative site II ligands, namely ketoprofen and diazepam. According to the crystal structure of HSA, the residues Arg-410 and Tyr-411 protrude into the centre of site II (in subdomain 3A), and the binding results showed that the guanidino moiety of Arg-410, the phenolic oxygen and the aromatic ring of Tyr-411 are important for ketoprofen binding. The guanidino moiety probably interacts electrostatically with the carboxy group of ketoprofen, the phenolic oxygen could make a hydrogen-bond with the keto group of the ligand, and the aromatic ring may participate in a specific stacking interaction with one of or both of the aromatic rings of ketoprofen. By contrast, Arg-410 is not important for diazepam binding. The two parts of Tyr-411 interact favourably with diazepam, and probably do so in the same way as with ketoprofen. In addition to its unique ligand binding properties, HSA also possesses an esterase-like activity, and studies with p-nitrophenyl acetate as a substrate showed that, although Arg-410 is important, the enzymic activity of HSA is much more dependent on the presence of Tyr-411. A minor activity could be registered when serine, but not alanine or phenylalanine, was present at position 411.

Alteration of human serum albumin tertiary structure induced by glycation. Spectroscopic study

2016 ◽  
Vol 153 ◽  
pp. 560-565 ◽  
Author(s):  
A. Szkudlarek ◽  
M. Maciążek-Jurczyk ◽  
M. Chudzik ◽  
J. Równicka-Zubik ◽  
A. Sułkowska
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Spectroscopic Study ◽  
Human Serum ◽  
Tertiary Structure

Different rates of formation of secondary and tertiary structure during renaturation of urea-denatured human serum albumin

1989 ◽  
Vol 54 (9) ◽  
pp. 2542-2549 ◽  
Author(s):  
Josef Chmelík
Keyword(s):  
Protein Folding ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Disulfide Bonds ◽  
Tertiary Structure ◽  
Hydrophobic Interactions ◽  
Protein Structures ◽  
Three Dimensional ◽  
Comparison Of The Results

A comparison of the results of our polarimetric measurements with the polarographic experiments reported earlier shows that the restoration of the secondary structure during the renaturation of human serum albumin is a process which is faster than the formation of the tertiary structure. These results, which are in agreement with the data on the kinetic control of protein folding, are discussed from the viewpoint of the importance of the individual types of interactions which take place during the formation and stabilization of three-dimensional protein structures. We have been able to demonstrate the great importance of electrostatic and hydrophobic interactions which together with the disulfide bonds are essential for the reversibility of the denaturation phenomena. The discussion also shows the essential role which evolution processes play in the selection of the mode of protein folding.

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