Showing papers on "Human serum albumin published in 2005"
TL;DR: Crystallographic analysis of 17 different complexes of HSA with a wide variety of drugs and small-molecule toxins reveals the precise architecture of the two primary drug-binding sites on the protein, identifying residues that are key determinants of binding specificity and illuminating the capacity of both pockets for flexible accommodation.
1,609 citations
TL;DR: The globular domain structural organization of monomeric HSA is at the root of its allosteric properties which are reminiscent of those of multimeric proteins.
Abstract: Human serum albumin (HSA), the most prominent protein in plasma, binds different classes of ligands at multiple sites HSA provides a depot for many compounds, affects pharmacokinetics of many drugs, holds some ligands in a strained orientation providing their metabolic modification, renders potential toxins harmless transporting them to disposal sites, accounts for most of the antioxidant capacity of human serum, and acts as a NO-carrier The globular domain structural organization of monomeric HSA is at the root of its allosteric properties which are reminiscent of those of multimeric proteins Here, structural, functional, biotechnological, and biomedical aspects of ligand binding to HSA are summarized
903 citations
TL;DR: A molecular spectroscopic investigation of the interaction between tetracyclines antibiotics and human serum albumin or bovine serumalbumin was reported and the action distances and the energy transfer efficiencies between donor-acceptor were calculated based on the Foster energy transference.
418 citations
TL;DR: Investigation of the mechanism of protein stabilization by sugars in the solid state finds that storage stability correlates best with "structure" as determined by FTIR spectroscopy, and while a specific interaction between stabilizer and protein might be responsible for the preservation of native structure, the evidence supporting this position is not compelling.
378 citations
TL;DR: The results of spectroscopic measurements and the thermodynamic parameters obtained suggest that hydrophobic interaction is the predominant intermolecular forces stabilizing the complex, which is also good agreement with the results of molecule modeling study.
346 citations
TL;DR: Methylglyoxal modification of critical arginine residues, whether experimental or physiological, is expected to disrupt protein-ligand interactions and inactivate enzyme activity by hydroimidazolone formation.
313 citations
TL;DR: Micropolarities in the two proteinous environments have been determined following the polarity sensitivity of the CT emission and addition of urea to the protein-bound systems leads to a reduction in the fluorescence anisotropy indicating the denaturation of the proteins.
Abstract: Interaction of 3-acetyl-4-oxo-6,7-dihydro-12H indolo-[2,3-a] quinolizine (AODIQ), a biologically active molecule, with model transport proteins, bovine serum albumin (BSA) and human serum albumin (HSA) have been studied using steady state and picosecond time-resolved fluorescence and fluorescence anisotropy. The polarity dependent intramolecular charge transfer (ICT) process is responsible for the remarkable sensitivity of this biological fluorophore to the protein environments. The CT fluorescence exhibits appreciable hypsochromic shift along with an enhancement in the fluorescence yield, fluorescence anisotropy (r) and fluorescence lifetime upon binding with the proteins. The reduction in the rate of ICT within the hydrophobic interior of albumins leads to an increase in the fluorescence yield and lifetime. Marked increase in the fluorescence anisotropy indicates that the probe molecule is located in a motionally constrained environment within the proteins. Micropolarities in the two proteinous environments have been determined following the polarity sensitivity of the CT emission. Addition of urea to the protein-bound systems leads to a reduction in the fluorescence anisotropy indicating the denaturation of the proteins. Polarity measurements and fluorescence resonance energy transfer (FRET) studies throw light in assessing the location of the fluorophore within the two proteinous media.
286 citations
TL;DR: The structures of the proteins as determined by circular dichroism indicate changes in the tertiary structure with the secondary structure remaining intact.
Abstract: In the context of this study, the noncovalent binding of selected phenolic compounds (chlorogenic, ferulic, and gallic acids, quercetin, rutin, and isoquercetin) to different proteins (human serum albumin, bovine serum albumin, soy glycinin, and lysozyme) was studied with direct (Hummel-Dreyer/size exclusion chromatography) and/or indirect methods (fluorescence absorbance properties of the binding components) In the latter case, the measurement of the phenol binding was achieved by exploiting the intrinsic fluorescence emission properties of quercetin as a probe From the data obtained, the binding constants and the number of binding sites were calculated The binding parameters were influenced by different factors, where, eg, increasing temperature and ionic strength as well as decreasing pH cause a diminished binding The structures of the proteins as determined by circular dichroism indicate changes in the tertiary structure with the secondary structure remaining intact
261 citations
TL;DR: A site-specific investigation of the relative affinities of binding sites on HSA for fatty acids (FA), the primary physiological ligand for the protein, establishes a protocol for direct probing of therelative affinITIES of FA-binding sites, one that may be extended to examine competition between FA and other ligands for specific binding sites.
Abstract: Human serum albumin (HSA) is a versatile transport protein for endogenous compounds and drugs. To evaluate physiologically relevant interactions between ligands for the protein, it is necessary to determine the locations and relative affinities of different ligands for their binding site(s). We present a site-specific investigation of the relative affinities of binding sites on HSA for fatty acids (FA), the primary physiological ligand for the protein. Titration of HSA with [13C]carboxyl-labeled FA was used initially to identify three NMR chemical shifts that are associated with high-affinity binding pockets on the protein. To correlate these peaks with FA-binding sites identified from the crystal structures of FA–HSA complexes, HSA mutants were engineered with substitutions of amino acids involved in coordination of the bound FA carboxyl. Titration of [13C]palmitate into solutions of HSA mutants for either FA site four (R410A/Y411A) or site five (K525A) within domain III of HSA each revealed loss of a specific NMR peak that was present in spectra of wild-type protein. Because these peaks are among the first three to be observed on titration of HSA with palmitate, sites four and five represent two of the three high-affinity long-chain FA-binding sites on HSA. These assignments were confirmed by titration of [13C]palmitate into recombinant domain III of HSA, which contains only sites four and five. These results establish a protocol for direct probing of the relative affinities of FA-binding sites, one that may be extended to examine competition between FA and other ligands for specific binding sites.
243 citations
TL;DR: It was proved that the fluorescence quenching of HSA by CS is a result of the formation of a CS-HSA complex and synchronous fluorescence spectroscopy data and UV-vis absorbance spectra have suggested that the association between CS and HSA changed the molecular conformation of H SA and the electrostatic interactions play a major role in CS-hSA association.
225 citations
TL;DR: The main mechanism of protein fluorescence quenching was a staticQuenching process and the hydroxyl groups of the drug in its neutral part played an important role in the binding process.
TL;DR: In this paper, the ability of human serum albumin to act as a boundary lubricant in joint prostheses using a pin-on-disc tribometer was investigated using a circular dichroism spectroscopy.
TL;DR: The interaction between Jatrorrhizine with human serum albumin (HSA) were studied by fluorescence quenching technique, circular dichroism (CD) spectroscopy, and Fourier transform infrared (FT-IR) spectra, which indicated that hydrophobic and electrostatic interactions played a major role in the binding of J atrorrhIZine to HSA.
TL;DR: A new method involving SA as fluorescence-enhancing reagent for estimation of BRD in aqueous samples has been suggested, and selective excitation of tryptophan residue results in emission from bromadiolone, thereby indicating a Förster type energy transfer from Trp to BRD.
TL;DR: Human serum albumin species with a bound Cys34 account for a large percentage of the composition of human serumalbumin preparations used for the treatment of critically ill patients, and the variability within lots from the same manufacturer is significant.
Abstract: Objective:Human serum albumin is indicated for the treatment of shock, acute restoration of blood volume, and in hypoalbuminemia. Conflicting reports are found in the literature for the clinical safety and efficacy of human serum albumin administration to critically ill patients. We sought to analyz
TL;DR: This detailed report of an in vitro reactivity difference between VOSO4 and BMOV may have bearing on the form of active vanadium metabolites delivered to target tissues.
Abstract: Significant new insights into the interactions of the potent insulin-enhancing compound bis(maltolato)oxovanadium(IV) (BMOV) with the serum proteins, apo-transferrin and albumin, are presented. Identical reaction products are observed by electron paramagnetic resonance (EPR) with either BMOV or vanadyl sulfate (VOSO4) in solutions of human serum apo-transferrin. Further detailed study rules out the presence of a ternary ligand-vanadyl-transferrin complex proposed previously. By contrast, differences in reaction products are observed for the interactions of BMOV and VOSO4 with human serum albumin (HSA), wherein adduct formation between albumin and BMOV is detected. In BMOV-albumin solutions, vanadyl ions are bound in a unique manner not observed in comparable solutions Of VOSO4 and albumin. Presentation of chelated vanadyl ions precludes binding at the numerous nonspecific sites and produces a unique EPR spectrum which is assigned to a BMOV-HSA adduct. The adduct species cannot be produced, however, from a solution Of VOSO4 and HSA titrated with maltol. Addition of maltol to a VOSO4-HSA solution instead results in formation of a different end product which has been assigned as a ternary complex, VO(ma)(HSA). Furthermore, analysis of solution equilibria using a model system of BMOV with 1-methylimidazole (formation constant log K = 4.5(1), by difference electronic absorption spectroscopy) lends support to an adduct binding mode (VO(ma)(2)-HSA) proposed herein for BMOV and HSA. This detailed report of an in vitro reactivity difference between VOSO4 and BMOV may have bearing on the form of active vanadium metabolites delivered to target tissues. Albumin binding of vanadium chelates is seen to have a potentially dramatic effect on pharmacokinetics, transport, and efficacy of these antidiabetic chelates.
TL;DR: Results showed that glycation altered the local structure around Trp-214 while not significantly impacting the secondary structure, and this alteration translated into an overall change in the stability of gHSA compared to HSA.
TL;DR: It is proposed that Cys chiefly works as a free radical scavenger whereas Met mainly acts as a metal chelator in relation to anti-/prooxidant properties of HSA.
Abstract: Antioxidant properties of human serum albumin (HSA) may explain part of its beneficial role in various diseases related to free radical attack. In the present study, the antioxidant role of Cys and Met was studied by copper-mediated oxidation of human low density lipoproteins and by free radical-induced blood hemolysis which essentially assessed metal-chelating and free radical scavenging activities, respectively. Mild conditions were set up to specifically modify Cys and Met residues by N-ethylmaleimide (NEM) and chloramine T treatments, respectively. We found that Met and Cys accounted for 40-80% of total antioxidant activity of HSA. Copper binding to HSA was decreased by about 50% with chloramine T treatment of Met whereas no change was observed after NEM treatment of Cys. Although other amino acid residues are likely to be involved in anti-/prooxidant properties of HSA, from our data, we propose that Cys chiefly works as a free radical scavenger whereas Met mainly acts as a metal chelator.
TL;DR: In this paper, the qualitative modification of albumin in hemodialysis patients (n = 20) was examined and their results were compared with healthy age-matched controls (N = 10).
TL;DR: Experimental results indicated that the combination reactions of colloidal gold and serum albumins were static quenching processes, and based on the effect of colloid gold on fluorescence intensity, the binding constants, the numbers of binding sites and the acting forces were found.
TL;DR: In this article, the binding of quercetin to human serum albumin (HSA) was studied and the binding constant measured by following the red-shifted absorption spectrum.
Abstract: Binding of quercetin to human serum albumin (HSA) was studied and the binding constant measured by following the red-shifted absorption spectrum of quercetin in the presence of HSA and the quenching of the intrinsic protein fluorescence in the presence of different concentrations of quercetin. Fluorescence lifetime measurements of HSA showed decrease in the average lifetimes indicating binding at a location, near the tryptophan moiety, and the possibility of fluorescence energy transfer between excited tryptophan and quercetin. Critical transfer distance (R
o
) was determined, from which the mean distance between tryptophan-214 in HSA and quercetin was calculated. The above studies were also carried out with bovine serum albumin (BSA).
TL;DR: The robustness and reproducibility of the optimized procedure was determined for three individual serum samples on three consecutive days, and an image analysis of the nine silver‐stained gels demonstrated that the intensity and localization of protein spots are highly reproducible.
Abstract: Serum is a readily available source for diagnostic assays, but the identification of disease-specific serum biomarkers has been impeded by the dominance of human serum albumin and immunoglobulins (Igs) in the serum proteome. There is a need to reduce the technical variation in serum processing and analysis to allow for a reproducible analysis of large cohorts. To this end, we have developed a rapid and reproducible procedure for sample preparation and high-resolution two-dimensional gel electrophoresis to analyze human serum. Serum is centrifuged at high speed to remove lipids and aggregated proteins, incubated with protein G resin to remove IgG, precipitated with NaCl/ethanol to deplete albumin, and slowly resolubilized in a sodium dodecyl sulfate (SDS)/N-(2-hydroxyethyl)piperazine-2'-(2-ethanesulfonic acid) (HEPES) buffer. The delipidated and IgG/albumin depleted serum proteins are focused on pH 4-7 linear large immobilized pH gradient strips, and then resolved by Bis-Tris SDS-polyacrylamide gel electrophoresis. The robustness and reproducibility of the optimized procedure was determined for three individual serum samples on three consecutive days. An image analysis of the nine silver-stained gels demonstrated that the intensity and localization of protein spots are highly reproducible. Our IgG and albumin depletion procedure will aid in screening the patient sera for normal biological variation and disease-specific biomarkers.
TL;DR: The stoichiometry of the KP1019 protein binding was determined through the molar Ru/S ratio and the KP 1019/Tf ratio is in the expected range for a sufficient uptake via the transferrin pathway.
Abstract: On-line 2-dimensional size exclusion/anion exchange chromatography was coupled to inductively coupled mass spectrometry with dynamic reaction cell technology (SEC-IC-ICP-MS) in order to characterize the interaction of the ruthenium-based anticancer drug KP1019 with human plasma proteins in vitro and, for the first time, in vivo. In SEC-ICP-MS studies the drug was found to bind exclusively to the protein fraction of 60–80 kDa in human plasma samples (clinical study/phase 1). The respective size fraction was collected and subsequently analyzed by reversed phase chromatography coupled to electrospray mass spectrometry (LC-ESI-MS) confirming the presence of the two well known transporter proteins, i.e. human serum albumin (HSA) and transferrin (Tf). Hence, for in vivo investigation of KP1019 interaction with HSA and Tf a fully automated SEC-IC-ICP-MS approach was applied. The stoichiometry of the KP1019 protein binding was determined through the molar Ru/S ratio. Human apo-Tf standards incubated with different stoichiometric equivalents of KP1019 were used for species-specific and species-unspecific calibration of the molar Ru/S ratio. Competitive in vitro incubation of KP1019 to both HSA and Tf for ca. 10 h showed that <20% of the overall KP1019 was found to bind to Tf in an equimolar mixture of Tf and HSA. This fraction dropped to 2% in the incubated mixture containing a 10-fold excess of HSA compared to Tf. This implied that less than 2% of KP1019 were expected to bind to Tf in human plasma samples, as they usually contain an even higher excess of HSA. Indeed, the concentration of the KP1019/Tf-adduct was below the limit of quantification in the plasma sample taken from a cancer patient treated with KP1019. Its fraction of the overall KP1019-content was estimated to be <1%. The KP1019/HSA stoichiometry in the plasma samples could be correlated with the individual infusions administered to the cancer patient within 26 days, the largest value being 1.4 (in the related sample, the KP1019/Tf stoichiometry was estimated to be in the range of 0.3–0.5). The KP1019/Tf ratio is in the expected range for a sufficient uptake via the transferrin pathway.
TL;DR: It is shown that quercetin in the presence of peroxidase/hydrogen peroxide covalently links to proteins with a particularly high affinity for HSA and that this also may occur in vivo after exposure to quERCetin.
Abstract: Quercetin is an abundant flavonoid in the human diet with numerous biological activities, which may contribute to the prevention of human disease but also may be potentially harmful. Quercetin is oxidized in cells to products capable of covalently binding to cellular proteins, a process that may be important for its biological activities. In the present study, using radiolabeled drug and quantifying the products after electrophoretic separation, proteins to which oxidized quercetin is binding irreversibly were identified. The binding of quercetin to human serum albumin (HSA) in human blood and the effect of stimulation of neutrophilic myeloperoxidase on this binding were also measured. The in vitro binding of quercetin to eight proteins in the presence of catalytic amounts of horseradish peroxidase and hydrogen peroxide was highly selective for HSA. For all proteins the binding was dramatically decreased by reduced L-glutathione. In the blood samples, the release of neutrophilic myeloperoxidase by phorbol ester caused a 3-fold increase in the binding of quercetin to HSA. This study shows that quercetin in the presence of peroxidase/hydrogen peroxide covalently links to proteins with a particularly high affinity for HSA and that this also may occur in vivo after exposure to quercetin. This provides further insights into the complex behavior of this major dietary flavonoid.
TL;DR: In this paper, a method for micro-contact imprinting CRP has been developed, where a series of non-imprinted polymers made without template, but with varying cross-linking agents, were made in order to produce a control polymer with minimal non-specific recognition.
TL;DR: The combination of a DNA construct containing the α Amy3 promoter and signal sequence, and the use of a rice suspension cell culture can provide an effective system for the production of recombinant pharmaceutical proteins.
Abstract: Human serum albumin (HSA) is the most widely used clinical serum protein. Currently, commercial HSA can only be obtained from human plasma, due to lack of commercially feasible recombinant protein expression systems. In this study, inducible expression and secretion of HSA by transformed rice suspension cell culture was established. Mature form of HSA was expressed under the control of the sucrose starvation-inducible rice alpha Amy3 promoter, and secretion of HSA into the culture medium was achieved by using the alpha Amy3 signal sequence. High concentrations of HSA were secreted into culture medium in a short time (2-4 days) by sucrose depletion after cell concentrations had reached a peak density in culture medium containing sucrose. The recombinant HSA had the same electrophoretic mobility as commercial HSA and was stable and free from apparent proteolysis in the culture medium. In a flask scale culture with repeated sucrose provision-depletion cycles, HSA was stably produced with yields up to 11.5% of total medium proteins or 15 mg/L per cycle after each sucrose provision-depletion cycle. A bubble column type bioreactor was designed for production of HSA. In the bioreactor scale culture, HSA was produced with yields up to 76.4 mg/L 4 days after sucrose depletion. HSA was purified from the culture medium to high purity by a simple purification scheme. Enrichment of HSA in culture medium simplifies downstream purification, minimizes protease degradation, and may reduce production cost. The combination of a DNA construct containing the alpha Amy3 promoter and signal sequence, and the use of a rice suspension cell culture can provide an effective system for the production of recombinant pharmaceutical proteins.
TL;DR: The results are encouraging towards the potential future application of PDI for the treatment of superficial wound infections caused by S. aureus, P. aeruginosa and C. albicans.
Abstract: Background Photodynamic inactivation (PDI) employs visible light and a photosensitizer to inactivate cells. The technique is currently clinically used for the treatment of several malignancies. However, the PDI of microorganisms still remains in the research phase. Purpose To study the effect of human blood plasma and human serum albumin (HSA) on the PDI of Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. Methods PDI experiments were performed using white light (30 mW cm−2) and the cationic 5-phenyl-10,15,20-tris(N-methyl-4-pyridyl)porphyrin chloride (TriP[4]) as photosensitizer. Results The microorganisms could be successfully photoinactivated by TriP[4] when suspended in phosphate buffered saline (PBS). In this medium, P. aeruginosa was the most resistant microorganism. Changing the suspending medium from PBS to human blood plasma reduced the PDI of all three microorganisms. In human blood plasma C. albicans was the most resistant microorganism. The same results were obtained with 4.5% and 7% HSA/PBS suspensions. Conclusions Albumin inhibits the PDI of S. aureus, P. aeruginosa and C. albicans in a dose dependent manner. However, our results are encouraging towards the potential future application of PDI for the treatment of superficial wound infections caused by S. aureus, P. aeruginosa and C. albicans.
TL;DR: The interactions of anthraquinone-albumin interactions were studied at different temperatures and in the presence of some metal ions and the Stern-Volmer curves suggested that the quenching occurring in the reactions was the staticQuenching process.
TL;DR: It was found that carbamazepine had direct competition with l-tryptophan, a probe for the indole-benzodiazepine site of HSA, but allosteric interactions with probes for the warfarin, tamoxifen and digitoxin sites.
TL;DR: In vitro adherence of Staphylococcus aureus and Pseudomonas aeruginosa on an albumin-coated and uncoated titanium surface is examined to show reduction is possible in bacterial contamination and infection of the HSA- coated titanium implant in vivo.
Abstract: Hypothesis: An albumin coating on titanium implants will inhibit bacterial adhesion on the implant surface Background: Bacterial, protein, and platelet adhesion on otologic implants and tympanostomy tubes is a major reason for implant sequelae and can eventually lead to implant removal The role of albumin coating of the implant in prevention of protein adhesion on implant surface has already been tested by the authors In the present study the authors examined the in vitro adherence of Staphylococcus aureus and Pseudomonas aeruginosa on an albumin-coated and uncoated titanium surface Methods: Human serum albumin (HSA)-coated and uncoated titanium surfaces were exposed to viable S aureus and P aeruginosa and, after washings, photographed by fluorescence microscopy to quantify the adhered bacteria, which was stained with acridine orange Results: Bacteria in the suspension adhered at a significantly lesser rate to the coated surfaces than to the uncoated surfaces, with overall bacterial adhesion dependent on bacterial concentration Binding of S aureus on HSA-coated surfaces was inhibited significantly (from 82 to 95% depending on concentration) Binding of P aeruginosa was inhibited from 29 to 37% Conclusion: Because albumin coating can reduce bacterial adherence on titanium surfaces in vitro, reduction is possible in bacterial contamination and infection of the HSA-coated titanium implant in vivo