Topic
Human serum albumin
About: Human serum albumin is a research topic. Over the lifetime, 9402 publications have been published within this topic receiving 269029 citations. The topic is also known as: serum albumin & ALB.
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TL;DR: Electronic absorption, EPR, and NMR spectroscopies indicate three specific and well-separated binding sites for CoII in HSA, where CoII ions in all three sites are in a high-spin state and coordinated in a distorted octahedral geometry.
Abstract: Human serum albumin (HSA) is the most abundant protein in the blood plasma and is involved in the transport of metal ions. Four metal-binding sites with different specificities have been described in HSA: (i) the N-terminal site provided by Asp1, Ala2, and His3, (ii) the site at the reduced Cys34, (iii) site A, including His67 as a ligand, and (iv) the nonlocalized site B. HSA can bind CoII, and HSA was proposed to be involved in CoII transport. Recently, binding of CoII to HSA has attracted much interest due to the so-called albumin cobalt binding (ACB) test approved by the Food and Drug Administration for evaluation of myocardial ischemia. Although the binding of CoII to HSA is important, the binding of CoII to HSA is not well-characterized. Here the binding of CoII to HSA was studied under anaerobic conditions to prevent CoII oxidation. Electronic absorption, EPR, and NMR spectroscopies indicate three specific and well-separated binding sites for CoII in HSA. CoII ions in all three sites are in a high...
101 citations
TL;DR: In this paper, the mechanism of interaction between C.I.Direct Yellow 9 and human serum albumin was studied using spectroscopic methods including fluorescence spectra, UV-vis, Fourier transform infrared (FT-IR) and circular dichroism (CD).
101 citations
TL;DR: A study of the effects of solution concentration and temperature showed that the initial adsorption rates on both polymers are proportional to the protein concentration raised to the 0.36 power, and that alkylation of the polymer increases the activation energy of the initial adhesion rate above the 14 kJ/mol observed for the underivatized polyurethane.
Abstract: The initial adsorption rate of delipidized Human Serum Albumin (HSA) is increased by addition of C-18 alkyl chains to a poly-urethane. The presence of alkyl chains does not appear to influence the total amount of HSA adsorbed after one hour exposure to a 5.0 mg/mL HSA solution. Neither does the desorption following one hour of adsorption appear to be influenced by the presence of alkyl chains. A study of the effects of solution concentration and temperature showed that the initial adsorption rates on both polymers are proportional to the protein concentration raised to the 0.36 power, and that alkylation of the polymer increases the activation energy of the initial adsorption rate above the 14 kJ/mol observed for the underivatized polyurethane. A new technique is presented to quantify the mass of adsorbed protein using Fourier transform infrared spectroscopy and attenuated total reflection optics. This technique uses the absorbance of bulk protein as an internal calibration reference, and appears to be as accurate and perhaps more precise than radiolabeling techniques.
100 citations
TL;DR: The steady-state emission data suggest that quercetin binds to two distinct sites in HSA from which the emissions from the normal tautomer and complex species take place, and the preliminary results of studies on emission decay kinetics are reported herein.
Abstract: Flavonols are plant pigments that are ubiquitous in nature. Quercetin (3,3',4',5,7-pentahydroxyflavone) and other related plant flavonols have come into recent prominence because of their usefulness as anticancer, antitumor, anti-AIDS, and other important therapeutic activities of significant potency and low systemic toxicity. Quercetin is intrinsically weakly fluorescent in aqueous solution, showing an emission maximum at approximately 538 nm. Upon binding to human serum albumin (HSA), quercetin undergoes dramatic enhancement in its fluorescence emission intensity, along with the appearance of dual emission behavior, consisting of normal and excited-state proton transfer (ESPT) fluorescence. In addition, the occurrence of a third emitting species has been noted for the first time. This is attributed to a electronic ground-state complex formed in the protein environment. High values of the fluorescence anisotropy (r) are obtained in the presence of HSA for the ESPT tautomer (r = 0.18), as well as the complex species (r = 0.37) of quercetin, indicating that the precursor ground-state molecules for both these emitting species of quercetin molecules are located in the motionally constrained sites of HSA. The steady-state emission data suggest that quercetin binds to two distinct sites in HSA from which the emissions from the normal tautomer and complex species take place. The preliminary results of studies on emission decay kinetics are also reported herein. Studies by far-UV circular dichroism spectroscopy reveal that binding of quercetin induces no significant perturbation in the secondary structure of HSA.
100 citations
TL;DR: Free, unbound antibiotic concentrations differed substantially between plasma and protein supplements and correlated well with antimicrobial efficacy, therefore, free, active concentrations should be measured in the test system instead of correcting for literature protein binding values.
Abstract: During antibiotic drug development, media are frequently spiked with either serum/plasma or protein supplements to evaluate the effect of protein binding Usually, previously reported serum or plasma protein binding values are applied in the analysis The aim of this study was to evaluate this approach by experimentally measuring free, unbound concentrations for antibiotics with reportedly high protein binding and their corresponding antimicrobial activities in media containing commonly used protein supplements Free, unbound ceftriaxone and ertapenem concentrations were determined in bacterial growth medium with and without bovine/human serum albumin, as well as adult bovine serum and human plasma using in vitro microdialysis The corresponding antimicrobial activity was determined in MIC and time-kill curve experiments using Escherichia coli ATCC 25922 and Streptococcus pneumoniae ATCC 6303 as test strains A semimechanistic maximum effect model was simultaneously fitted to the data and respective EC(50) (concentration at half-maximum effect) values compared Protein binding differed significantly for ceftriaxone (P < 005) between human plasma (768 +/- 110%) and commercially available bovine (202 +/- 83%) or human serum albumin (569 +/- 166%) Similar results were obtained for ertapenem (human plasma, 738 +/- 116%; bovine serum albumin, 124 +/- 48%; human serum albumin, 178 +/- 115%) The MICs and EC(50)s of both strains were significantly increased (P < 005) for ceftriaxone when comparing human and bovine serum albumin, whereas the EC(50)s were not significantly different for ertapenem Free, unbound antibiotic concentrations differed substantially between plasma and protein supplements and correlated well with antimicrobial efficacy Therefore, free, active concentrations should be measured in the test system instead of correcting for literature protein binding values
100 citations