Mechanism of denaturation of human serum albumin by urea

1988 ◽  
Vol 53 (2) ◽  
pp. 411-422 ◽  
Author(s):  
Josef Chmelík ◽  
Pavel Anzenbacher ◽  
Jitka Chmelíková ◽  
Milada Matějčková ◽  
Vítěz Kalous
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Disulfide Bonds ◽  
Polyacrylamide Gel Electrophoresis ◽  
Helical Structure ◽  
Random Coil ◽  
Gel Chromatography ◽  
Uv Spectrophotometry ◽  
Comparison Of The Results

The mechanism of denaturation of human serum albumin by urea was examined by polarography, polarimetry, circular dichroism, UV-spectrophotometry, gel chromatography, and polyacrylamide gel electrophoresis. Comparison of the results obtained by these methods shows that this reaction is a complex process which cannot be described by a two-state denaturation model. It has been demonstrated that the different states which denaturation produces arise under different denaturation conditions. The different behavior of various species of human serum albumin (monomer, mercaptalbumin and nonmercaptalbumin) during denaturation by urea was examined. As a result the following probable denaturation scheme was proposed: The denaturation of human serum albumin by urea is regarded as a stepwise process involving one stable intermediary product at least ( demonstrated electrophoretically). After the rapid initial change of the ordered helical structure extensive hydrophobic domains of the molecule remain folded. Cystine residues are gradually liberated from these domains. Denaturated mercaptalbumin has the conformation of a random coil in which the pairing of native disulfide bonds has been altered because of SH-S-S interchange reactions; in contrast native disulfide bonds are retained in nonmercaptalbumin.

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.

scholarly journals Systematic FTIR Spectroscopy Study of the Secondary Structure Changes in Human Serum Albumin under Various Denaturation Conditions

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 359 ◽  
Author(s):  
Usoltsev ◽  
Sitnikova ◽  
Kajava ◽  
Uspenskaya
Keyword(s):  
Secondary Structure ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Ftir Spectroscopy ◽  
Conformational Changes ◽  
Data Interpretation ◽  
Random Coil ◽  
Helical Conformation ◽  
Structure Changes

Human serum albumin (HSA) is the most abundant protein in blood plasma. HSA is involved in the transport of hormones, fatty acids, and some other compounds, maintenance of blood pH, osmotic pressure, and many other functions. Although this protein is well studied, data about its conformational changes upon different denaturation factors are fragmentary and sometimes contradictory. This is especially true for FTIR spectroscopy data interpretation. Here, the effect of various denaturing agents on the structural state of HSA by using FTIR spectroscopy in the aqueous solutions was systematically studied. Our data suggest that the second derivative deconvolution method provides the most consistent interpretation of the obtained IR spectra. The secondary structure changes of HSA were studied depending on the concentration of the denaturing agent during acid, alkaline, and thermal denaturation. In general, the denaturation of HSA in different conditions is accompanied by a decrease in α-helical conformation and an increase in random coil conformation and the intermolecular β-strands. Meantime, some variation in the conformational changes depending on the type of the denaturation agent were also observed. The increase of β-structural conformation suggests that HSA may form amyloid-like aggregates upon the denaturation.

Rapid detection and initial characterization of genetic variants of human serum albumin

1991 ◽  
Vol 37 (7) ◽  
pp. 1221-1224 ◽  
Author(s):  
J Merle Sheat ◽  
Robert J Peach ◽  
Peter M George
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Genetic Variants ◽  
Gel Electrophoresis ◽  
Structural Changes ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl

Abstract We have studied the detection and classification of genetic variants of human serum albumin by electrophoresis. Samples from 10 patients who were heterozygous for eight different albumin variants were studied by two methods. In agarose gel electrophoresis, each of these variants has an abnormal mobility and can be classified on the basis that structural changes at the N-terminus abolish 63Ni binding. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole serum, glycosylated variants are easily detected because of their greater apparent molecular mass.

The Effects of 1-Propanol on Behaviour of Human Serum Albumin in Alkaline Solution

1993 ◽  
Vol 58 (2) ◽  
pp. 267-280
Author(s):  
Vladimír Karpenko ◽  
Rostislav Škrabana
Keyword(s):  
Fatty Acids ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Conformational Transition ◽  
Point Of View ◽  
Uv Spectrophotometry ◽  
Fourth Derivative ◽  
Ph Range ◽  
Albumin Molecule

The effects of 1-propanol ant to a certain extent of ethanol on human serum albumin were studied over the pH range 7 - 13.3 and alcohol concentrations up to 20 vol.%. In some case behaviour of the native preparation was compared with albumin cleared of weaker bound fatty acids. The data obtained by UV-spectrophotometry were discussed from the point of view of individual types of chromophores as well as in a broader context of the secondary structure. The results can be summarized as follows: (a) Partial removal of bound fatty acids has an influence on the dissociation of tyrosines. (b) The effect of alcohols on this dissociation is rather complex, the permitivity of the solvent being only a part of it. (c) At high alkaline pH a series of peaks in the fourth-derivative absorption spectra appear in the region 305 - 320 nm. These peaks were shown to correspond to buried dissociated tyrosines. (d) In the presence of 1-propanol a small conformational transition of albumin molecule is observed at pH below 9.

Microheterogeneity of human serum albumin: evidence for differences in reducibility of disulfide linkages

1968 ◽  
Vol 46 (8) ◽  
pp. 789-795 ◽  
Author(s):  
A. F. S. A. Habeeb
Keyword(s):  
Human Serum Albumin ◽  
Sodium Dodecyl Sulfate ◽  
Serum Albumin ◽  
Human Serum ◽  
Disulfide Bonds ◽  
Free Amino ◽  
Sodium Dodecyl ◽  
Amino Groups ◽  
Trinitrobenzenesulfonic Acid ◽  
Disulfide Linkages

Studies were designed to determine the causes of the microheterogeneity of human serum albumin. Human serum albumin in 3 M KCl was fractionated in a stepwise manner by lowering the pH. The resultant fractions showed similarities in: (a) the reactivity of ε-amino groups with trinitrobenzenesulfonic acid, (b) the binding of sodium dodecyl sulfate to the free amino groups, and (c) the ability to precipitate with anti-human serum albumin. Conversely, differences existed in the susceptibility to reduction of disulfide bonds of the various fractions with β-mercaptoethanol, which suggested that the microheterogeneity of human serum albumin and its fraction may be due, in part at least, to differences in the pairing of the disulfide bonds.

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