Showing papers on "Human serum albumin published in 2004"
TL;DR: The distance constraints obtained for lysine residues using various cross-linkers should be valuable in assisting the determination of the 3-D structure of BSA.
478 citations
TL;DR: It was found that the hydroxyls substituted on aromatic ring of the drugs play an important role in the changes of protein's secondary structure after interaction with the three drugs.
460 citations
TL;DR: C‐reactive protein (CRP), a diagnostic marker of rheumatoid arthritis (RA), was detected in serum samples taken from patients with either erosive or nonerosive RA and compared to healthy individuals using an immunoassay.
Abstract: A general method for the quantification of proteins in human serum was developed using mass spectrometry (MS) and stable isotope-labeled synthetic peptides as internal standards. Using this approach, C-reactive protein (CRP), a diagnostic marker of rheumatoid arthritis (RA), was detected in serum samples taken from patients with either erosive or nonerosive RA and compared to healthy individuals. Small volumes of serum samples were enriched for low-abundance proteins through the selective removal of human serum albumin (HSA), immunoglobulin G (IgG), and haptoglobin. After depletion of abundant proteins, the complexity of the protein mixture was further simplified using size exclusion chromatography (SEC) to fractionate denatured proteins into discrete molecular weight ranges. Fractions of interest containing CRP, M(r) = 25 000, were pooled, digested with trypsin, and then fixed quantities of the synthetic peptides were added to the mixture. The mixture of tryptic peptides was subsequently analyzed by nanoflow chromatography-tandem MS (nanoLC-MS/MS) using multiple-reaction monitoring (MRM) on a triple quadrupole mass spectrometer (TQ-MS). The ratio of transition ions derived from the endogenous and isotope-labeled peptides provided a quantitative measure of CRP in the original samples as assessed by independent measurement of CRP in the same patient samples using an immunoassay. The use of isotope-labeled synthetic peptides and MRM is a powerful analytical method for the prescreening of candidate protein biomarkers in human serum prior to antibody and immunoassay development.
433 citations
TL;DR: The interactions of chlorogenic acid and ferulic acid with human serum albumin (HSA) have been investigated by fluorescence and Fourier transformed infrared (FT-IR) spectrometry and indicated a partial unfolding of HSA in the presence of the two acids.
429 citations
TL;DR: In this paper, the interaction of quercetin, rutin, hyperin, and baicalin with human serum albumin (HSA) was studied, and the effect of various metal ions on the binding constants of these compounds with HSA was also studied.
389 citations
TL;DR: By the analysis of fluorescence spectrum and fluorescence intensity, it was showed that BCPT has a strong ability to quench the intrinsic fluorescence of both bovine serum albumin and human serumalbumin through a static quenching procedure.
337 citations
TL;DR: Experimental results and theoretical data clarified that HNF could bind to HSA and be effectively transported and eliminated in body, which could be a useful guideline for further drug design.
Abstract: In this work, the binding of 2-hydroxy-3-nitro-9-fluorenone (HNF; a new reagent with antitumour activity) to human serum albumin (HSA) was investigated by fluorescence spectroscopy combined with UV-Vis absorption, circular dichroism (CD), and Fourier transform infrared (FT-IR) spectrophotometric techniques under simulative physiological conditions for the first time. A strong fluorescence quenching reaction of HNF to HSA was observed and the quenching mechanism was suggested as static quenching according to the Stern–Volmer (S–V) equation. The binding constants of HNF with HSA at 300, 310 and 320 K were calculated as 6.08×10 5 , 3.80×10 5 and 2.79×10 5 M −1 , respectively, and corresponding numbers of binding sites ( n ) were 1.1, 1.0 and 1.0. Experimental results observed showed that the binding of HNF to HSA induced conformational change of HSA. The quantitative analysis data of CD spectra from that of the α-helix 60.3% in free HSA to 56.5% in the HNF–HSA complex further confirmed that the secondary structure of the protein was modified by HNF. The thermodynamic parameters, standard enthalpy change (Δ H °) and the standard entropy change (Δ S °), were obtained to be −31.10 kJ mol −1 and 6.87 J mol −1 K −1 , respectively, which indicated that a hydrophobic force played a major role in the interaction of HNF with HSA. All these experimental results and theoretical data clarified that HNF could bind to HSA and be effectively transported and eliminated in body, which could be a useful guideline for further drug design.
263 citations
TL;DR: The binding of scutellarin with human serum albumin (HSA) was investigated by fluorescence, circular dichroism, Fourier transform infrared spectroscopy, and molecular modeling study and suggested that scutellerin can strongly bind to the HSA and the primary binding site is located in site I of HSA.
250 citations
TL;DR: A decrease in serum albumin of >0.3 g/dL that persists for a period of 6 weeks is associated a decrease in albumin synthesis, associated with evidence of activation of the acute phase response (inflammation) but not with changes in enPCR.
205 citations
TL;DR: Results suggest that the primary binding site for methyl parathion on albumin is close to tryptophan residues 214 of human serum albumin and 212 of bovine serum albumIn, and suggest that this pesticide is potentially toxic for both vertebrates and invertebrates.
204 citations
TL;DR: The results indicate that nanoparticles conjugated with an antibody against a specific tumour antigen holds promise, as selective drug delivery systems for the treatment of tumours expressing a specific cancer antigen.
Abstract: Nanoparticles represent useful drug delivery systems for the specific transport of drugs to tumour cells. In the present study biodegradable nanoparticles based on gelatin and human serum albumin (HSA) were developed. The surface of the nanoparticles was modified by covalent attachment of the biotin–binding protein NeutrAvidin™ enabling the binding of biotinylated drug targeting ligands by avidin–biotin-complex formation. Using the HER2 receptor specific antibody trastuzumab (Herceptin®) conjugated to the surface of these nanoparticles, a specific targeting to HER2-overexpressing cells could be shown. Attachment of the antibody-conjugated nanoparticles to the surface of HER2-overexpressing cells was time and dose dependent. Confocal laser scanning microscopy demonstrated an effective internalisation of the nanoparticles by HER2-overexpressing cells via receptor-mediated endocytosis. The results indicate that nanoparticles conjugated with an antibody against a specific tumour antigen holds promise, as sele...
TL;DR: Findings indicate that pre-coating of nanoparticles with serum albumin could be useful to prevent their rapid clearance by mononuclear phagocyte system in vivo, and impaired subsequent association of serum proteins onto the surface is indicated.
TL;DR: Transcytosis of MPO by caveolae induced by its charge-dependent interaction with albumin is an important means of delivering MPO to the subendothelial space and albumin-mediated transport of MPo may thereby regulate NO bioavailability and formation of NO-derived oxidants in the vessel wall.
Abstract: Myeloperoxidase (MPO), the phagocyte hemoprotein involved in neutrophil host defense and consuming nitric oxide (•NO), induces the nitration of extracellular matrix proteins and tissue remodeling subsequent to its transcytosis across the endothelial barrier. We addressed the role of an interaction of MPO with albumin as a requirement for MPO transport across the endothelium. Matrix-assisted laser desorption/ionization MS analysis of 80- and 60-kDa proteins purified from human lung tissue [with a human serum albumin (HSA)-affinity column] identified these albumin-binding proteins as MPO and MPO-heavy chain. A peptide corresponding to the MPO-heavy chain residues 425–454 demonstrated high-affinity binding to HSA. Replacement of the positively charged residues, R and K with G, prevented the binding of HSA to the peptide. We observed that albumin increased the binding of 125I-MPO to lung microvascular endothelial cells by 2-fold and the rate of transendothelial flux of 125I-MPO in cultured monolayers and intact vessels. Disruption of caveolae with cyclodextrin prevented the albumin-induced increase in transendothelial flux of 125I-MPO. We also observed by confocal imaging that albumin induced the rapid internalization of MPO and its colocalization with albumin-labeled vesicles. MPO colocalized with the caveolae markers cholera toxin subunit B and caveolin 1 in the endocytosed vesicles. Thus, transcytosis of MPO by caveolae induced by its charge-dependent interaction with albumin is an important means of delivering MPO to the subendothelial space. Albumin-mediated transport of MPO may thereby regulate NO bioavailability and formation of NO-derived oxidants in the vessel wall.
TL;DR: All corroles (2, 2-Ga, and 2-Mn) may be considered as fully conjugated at biologically relevant HSA concentrations, and high-affinity binding sites, close to the unique tryptophan, are fully occupied at very low concentrations.
TL;DR: The relative fluorescence intensity of the paclitaxel-bound HSA decreased, suggesting that perturbation around the Trp 214 residue took place, and this was confirmed by the destabilization of the warfarin binding site, which includes Trp214, and high affinity bilirubin binding sites located in subdomain IIA.
TL;DR: Results demonstrated the suitability of CE‐ICP‐MS as a rapid assay for high‐throughput studying of drug/HSA interactions, and confirmed a specific affinity of cisplatin and novel Pt complexes to HSA.
Abstract: Characterizing how platinum metallocomplexes bind to human serum albumin (HSA) is essential in evaluating anticancer drug candidates. Using cisplatin as a reference complex, the application of capillary electrophoresis (CE) to reliably assess drug/HSA interactions was validated. Since this complex is small compared to the size of the protein, the binding response could only be recognized when applying CE coupled to a (platinum) metal-specific mode of detection, namely inductively coupled plasma-mass spectrometry (ICP-MS). This coupling allowed for confirmation of a specific affinity of cisplatin and novel Pt complexes to HSA, measurement of the kinetics of binding reactions, and determination of the number of drug molecules attached to the protein. As the cisplatin/HSA molar ratio increased, the reaction rate became faster with a maximum on the kinetic curve appearing at about 50 h of incubation at 20 times excess of cisplatin. The reaction was characterized as a pseudo-first order reaction with the rate constant k = 0.003 min−1 at 37°C. When incubated with a 20-fold excess of cisplatin, HSA bound up to 10 mol of Pt per mol of the protein. This is indicative for a strong metal-protein coordination occurring at several HSA sites other than the only protein cysteine residue. Structural analogs of cisplatin, bearing aminoalcohol ligands, showed comparable protein binding reactivity and stoichiometry but a common equilibrium was not reached even after one week of incubation. Also apparent was a two-step mechanism of the binding reaction. Results demonstrated the suitability of CE-ICP-MS as a rapid assay for high-throughput studying of drug/HSA interactions.
TL;DR: Several immobilization methods were explored for the preparation of high-performance affinity monolithic columns containing human serum albumin (HSA), and the greatest amount of immobilized HSA was obtained by the Schiff base method, whereas the epoxy method gave the lowest protein content.
Abstract: Several immobilization methods were explored for the preparation of high-performance affinity monolithic columns containing human serum albumin (HSA). These monoliths were based on a copolymer of glycidyl methacrylate and ethylene dimethacrylate. In one method, the epoxy groups of this copolymer were used directly for the immobilization of HSA through its amine residues (i.e., the epoxy method); in other approaches, these epoxy groups were converted to diols for later use in the carbonyldiimidazole, disuccinimidyl carbonate, and Schiff base methods. Each HSA monolith was evaluated in terms of its total protein content and its retention of several model compounds, including (R/S)-warfarin and D/L-tryptophan. The greatest amount of immobilized HSA was obtained by the Schiff base method, whereas the epoxy method gave the lowest protein content. The Schiff base method also gave the best resolution in chiral separations of (R/S)-warfarin and D/L-tryptophan. All of the immobilization methods gave similar relative activities for HSA in its binding to (R)- and (S)-warfarin, but some differences were noted in the activity of the immobilized HSA for D- and L-tryptophan. The efficiency of these monoliths was found to be greater than that of silica-based HSA columns for (R/S)-warfarin (i.e., analytes with high retention), but little or no difference was seen for D- and L-tryptophan (analytes with weak retention).
TL;DR: The data show that flavonoid intestinal and hepatic metabolism have profound effects on ability to inhibit LDL oxidation and to bind to human albumin, in comparison to free flavonoids and other quercetin conjugates.
Abstract: Quercetin is an important dietary flavonoid with in vitro antioxidant activity. However, it is found in human plasma as conjugates with glucuronic acid, sulfate or methyl groups, with no significant amounts of free quercetin present. The antioxidant properties of the conjugates found in vivo and their binding to serum albumin are unknown, but essential for understanding possible actions of quercetin in vivo. We, therefore, tested the most abundant human plasma quercetin conjugates, quercetin-3-glucuronide, quercetin-3'-sulfate and isorhamnetin-3-glucuronide, for their ability to inhibit Cu(II)-induced oxidation of human low density lipoprotein and to bind to human albumin, in comparison to free flavonoids and other quercetin conjugates. LDL oxidation lag time was increased by up to four times by low ( quercetin > quercetin-3-glucuronide = quercetin-3-glucoside > catechin > quercetin-4'-glucuronide > isorhamnetin-3-glucuronide > quercetin-3'-sulfate. Thus the proposed products of small intestine metabolism (quercetin-7-glucuronide, quercetin-3-glucuronide) are more efficient antioxidants than subsequent liver metabolites (isorhamnetin-3-glucuronide, quercetin-3'-sulfate). Albumin-bound conjugates retained their property of protecting LDL from oxidation, although the order of efficacy was altered (quercetin-3'-sulfate > quercetin-7-glucuronide > quercetin-3-glucuronide > quercetin-4'-glucuronide = isorahmnetin-3-glucuronide). Kq values (concentration required to achieve 50% quenching) for albumin binding, as assessed by fluorescence quenching of Trp214, were as follows: quercetin-3'-sulfate (approximately 4 microM)= quercetin > or = quercetin-7-glucuronide > quercetin-3-glucuronide = quercetin-3-glucoside > isorhamnetin-3-glucuronide > quercetin-4'-glucuronide (approximately 20 microM). The data show that flavonoid intestinal and hepatic metabolism have profound effects on ability to inhibit LDL oxidation and a lesser but significant effect on binding to serum albumin.
TL;DR: Adsorption studies by radiolabeling of albumin suggest that rapid HSA adsorption takes place on both surfaces, reaching a maximum value after approximately 60 min of incubation.
Abstract: In the present work, the adsorption of human serum albumin (HSA) on commercially pure titanium with a titanium oxide layer formed in a H(2)O(2) solution (TiO(2) cp) and on TiO(2) sputtered on Si (TiO(2) sp) was analyzed. Adsorption isotherms, kinetic studies, and work of adhesion determinations were carried out. HSA exchangeability was also evaluated. Surface characterization was performed by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and wettability studies. The two TiO(2) surfaces have very distinct roughnesses, the TiO(2) sp having a mean R(a) value 14 times smaller than the one of TiO(2) cp. XPS analysis revealed consistent peaks representative of TiO(2) on sputtered samples as well as on Ti cp substrate after 48 h of H(2)O(2) immersion. Nitrogen was observed as soon as protein was present, while sulfur, present in disulfide bonds in HSA, was observed for concentrations of protein higher than 0.30 mg/mL. The work of adhesion was determined from contact angle measurements. As expected from the surface free energy values, the work of adhesion of HSA solution is higher for the TiO(2) cp substrate, the more hydrophilic one, and lower for the TiO(2) sp substrate, the more hydrophobic one. The work of adhesion between plasma and the substrates assumed even higher values for the TiO(2) cp surface, indicating a greater interaction between the surface and the complex protein solutions. Adsorption studies by radiolabeling of albumin ((125)I-HSA) suggest that rapid HSA adsorption takes place on both surfaces, reaching a maximum value after approximately 60 min of incubation. For the higher HSA concentrations in solution, a multilayer coverage was observed on both substrates. After the adsorption step from single HSA solutions, the exchangeability of adsorbed HSA molecules by HSA in solution was evaluated. The HSA molecules adsorbed on TiO(2) sp seem to be more easily exchanged by HSA itself than those adsorbed on TiO(2) cp after 24 h. In contrast, after 72 h, nearly all the adsorbed albumin molecules effectively exchange with other albumin molecules.
TL;DR: The ability of peptide:PEOtethers to inhibit protein adsorption appeared to be a function of type and surface coverage of the PEO tether and not influenced by the amount or molecular structure the tethered peptide.
TL;DR: In a rabbit model of carotid artery injury, MnL1 clearly delineated both arteries and veins while also distinguishing between healthy tissue and regions of vessel damage.
Abstract: The manganese(II) ion has many favorable properties that lead to its potential use as an MRI contrast agent: high spin number, long electronic relaxation time, labile water exchange. The present work describes the design, synthesis, and evaluation of a novel Mn(II) complex (MnL1) based on EDTA and also contains a moiety that noncovalently binds the complex to serum albumin, the same moiety used in the gadolinium based contrast agent MS-325. Ultrafiltration albumin binding measurements (0.1 mM, pH 7.4, 37 degrees C) indicated that the complex binds well to plasma proteins (rabbit: 96 +/- 2% bound, human: 93 +/- 2% bound), and most likely to serum albumin (rabbit: 89 +/- 2% bound, human 98 +/- 2% bound). Observed relaxivities (+/- 5%) of the complex were measured (20 MHz, 37 degrees C, 0.1 mM, pH 7.4) in HEPES buffer (r(1) = 5.8 mM(-)(1) s(-)(1)), rabbit plasma (r(1) = 51 mM(-)(1) s(-)(1)), human plasma (r(1) = 46 mM(-)(1) s(-)(1)), 4.5% rabbit serum albumin (r(1) = 47 mM(-)(1) s(-)(1)), and 4.5% human serum albumin (r(1) = 48 mM(-)(1) s(-)(1)). The water exchange rate was near optimal for an MRI contrast agent (k(298) = 2.3 +/- 0.9 x 10(8) s(-)(1)). Variable temperature NMRD profiles indicated that the high relaxivity was due to slow tumbling of the albumin-bound complex and fast exchange of the inner sphere water. The concept of a high relaxivity Mn(II)-based contrast agent was validated by imaging at 1.5 T. In a rabbit model of carotid artery injury, MnL1 clearly delineated both arteries and veins while also distinguishing between healthy tissue and regions of vessel damage.
TL;DR: The crystal structure of HSA in complex with the GA module of protein PAB offers a molecular explanation to this unusually clear example of bacterial adaptation.
TL;DR: Confocal laser scanning microscopy revealed that nanoparticles crosslinked with low amounts of glutaraldehyde, rapidly degraded intracellularly, leading to a significant accumulation of the ASO in cytosolic compartments of the tumour cells.
TL;DR: It is shown that Lys525 is a predominant site of N-homocysteinylation in human serum albumin in vitro and in vivo and that the reactivity of albumin lysine residues, including Lys525, is affected by the status of Cys34.
TL;DR: The developed immunoassay system using fluorescence dye and lateral-flow chromatography is a simple, fast and reliable method for quantifying the albumin concentration in whole blood.
TL;DR: Interaction of meso-substituted anionic thiacarbocyanines with HSA results in cis-->trans isomerization and, as a consequence, an appearance and a steep rise of dye fluorescence.
TL;DR: Time-resolved measurements using laser flash photolysis reveal the presence of two components with different lifetimes in triplet decay, which are ascribed to the CP/HSA complexes in site I, where stereodifferentiation is more important.
Abstract: A remarkable stereodifferentiation has been observed in the interaction between the excited triplet state of carprofen (CP) and human serum albumin (HSA). Time-resolved measurements using laser flash photolysis reveal the presence of two components with different lifetimes in triplet decay. This is explained by complexation of CP to the two possible HSA binding sites. The shorter-lived components are ascribed to the CP/HSA complexes in site I, where stereodifferentiation is more important (tauR/tauS ca. 4). This is correlated with formation of a dehalogenated photoproduct upon steady-state photolysis.
TL;DR: Both complexes containing the 6-maleimido-4-oxacaproic ester showed good water solubility and CE experiments revealed rapid binding to human serum albumin and the formation of biadducts with dGMP and dAMP.
TL;DR: Compound 9 (CJC-1131) having the point of attachment to albumin at the C-terminal of GLP-1 and a D-alanine substitution at position 8 was identified as having the best combination of stability and bioactivity.