Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0393754 (HSA)
 2,996 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An extensive study was carried out on HSA and non-enzymatically glycated HSA by enzymatic digestion with trypsin and endoproteinase Lys-C, with the aim of identifying specific glycated peptides deriving from enzymatic digestion of glycated HSA. They may be considered, in pectore, as advanced glycation end products/peptides. These compounds, important at a systemic level in diabetic and nephropathic subjects, are produced by enzymatic digestion of in vivo glycated proteins: They are related to the pathological state of patients and have been invoked as responsible for tissue modifications. The digested mixtures obtained by the two enzymes were analyzed by MALDI/MS and LC/ESI/MSn, and clear cut differences were found. First of all, the digestion products of glycated HSA are generally less abundant than those observed in the case of unglycated HSA, accounting for the lower proclivity of the former to enzymatic digestion. MS/MS experiments on doubly charged ions, comparisons with a protein database, and molecular modeling to identify the lysine NH2 groups most exposed to glycation, identified some glycated peptides in digestion mixtures obtained from both types of enzymatic digestion. Residues 233K, 276K, 378K, 545K, and 525K seem to be privileged glycation sites, in agreement with the fractional solvent accessible surface values calculated by molecular modeling.
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PMID:Enzymatic digestion and mass spectrometry in the study of advanced glycation end products/peptides. 1504 55

Boron neutron capture therapy (BNCT) is a promising binary treatment for cancer. BNCT is based on the ability of the nonradioactive isotope (10)B to capture, with a very high probability, thermal neutrons. This nuclear reaction results in two particles (an alpha and a lithium nucleus). The particles have a high biological effectiveness, which is limited in tissue to approximately the diameter of one cell. If the reaction can be limited to a tumor cell, the physical characteristic opens up the possibility to selectively destroy cancer cells, while sparing the surrounding healthy tissue. Quality control of (10)B-containing compounds and their distribution at present are very important, and different analytical methods have been developed, such as time-of-flight secondary ion mass spectrometry (TOF-SIMS), electron energy loss spectrometry (EELS), prompt gamma analysis and inductively coupled plasma-optical emission spectrometry (ICP-OES). These methods allow the analyses of (10)B, but it is not possible to characterize the specific molecular compounds containing (10)B. For this reason, we propose a fast and quantitative method that permits the determination of closo-undecahydro-1-mercaptododecaborate (BSH) and (10)boron-phenylalanine (BPA) and their eventual metabolites. In particular, (10)B-containing compounds are detected by means of flow-injection electrospray tandem mass spectrometry (FI/ESI-MS/MS). This approach allows the identification of Boron compounds, BSH and BPA, using tandem mass spectrometry, and quantitative analysis is also possible (c.v. +/-4.7%; n = 5; linear range 10-10,000 ng/ml). Furthermore, (10)B-containing compounds were detected in actual biological sample (urine and plasma, diluted 10,000- and 1,000-fold, respectively) injecting a small volume (1 microl) of diluted samples.
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PMID:Analysis of 10B antitumoral compounds by means of flow-injection into ESI-MS/MS. 1632 Feb 99

Boron neutron capture therapy (BNCT) is a bimodal radiotherapeutic treatment based on the irradiation of neoplastic tissues with neutrons after the tissues have selectively accumulated molecules loaded with nuclides with large neutron capture cross-sections (such boron-10). Boron-10 carriers have been tested to a limited extent, and clinical trials have been conducted on sulfhydryl borane (10B-BSH) and boronophenylalanine (10B-BPA). However, precise and accurate measurements of boron-10 concentrations (0.1-100 microg/g) in specimens and samples of limited size (microg scale) are needed in order to be able to biologically characterise new compounds in predictive tissue dosimetry, toxicology and pharmacology studies as well as in clinical investigations. A new approach based on fast separation and detection of 10B-BPA performed by coupling capillary electrophoresis to electrospray mass spectrometry is reported. This method allows the quantitative analysis and characterisation of 10B-BPA in a short time with a high separation efficiency. Detection limits of 3 microM for 10B-BPA and 30 ng/mL for 10B were obtained with CE-ESI-MS. A quantification limit of 10 microM for 10B-BPA (100 ng/mL for 10B) was attained. The total boron-10 concentration was determined by high-resolution inductively coupled mass spectrometry in order to validate the method. Boron-10 isotope measurements were carried out by HR-ICP-MS at medium resolution (R=4000) due to the presence of an isobaric interference at mass 10. Good agreement was obtained between the values from CE-ESI-MS and those from HR-ICP-MS. The method has been successfully used to determine the 10B-BPA in two lines of cultured cells.
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PMID:Capillary electrophoresis-electrospray mass spectrometry and HR-ICP-MS for the detection and quantification of 10B-boronophenylalanine (10B-BPA) used in boron neutron capture therapy. 1637 82

The preparation and optimization of a new monolithic chymotrypsin bioreactor for online protein digestion is described. Silica monolithic supports have been activated with epoxide functionalities following an optimized in situ procedure and used for covalent immobilization of chymotrypsin in one-step reaction under different conditions. A total of four bioreactors were prepared and characterized in terms of the amount of immobilized enzyme and apparent active units by using a standard substrate, N-benzoyl-L-tyrosine p-nitroanilide (BTPNA). The stability of the bioreactors was evaluated and the morphology of the support after immobilization and use was studied by SEM analysis. The proteolytic activity of the optimized chymotrypsin bioreactor was evaluated using HSA as a model protein by online coupling of the bioreactor with LC-ESI-MS. With the online protocol, complete protein digestion in 120 min was achieved with a sequence coverage of 97.3%.
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PMID:Chymotrypsin immobilization on epoxy monolithic silica columns: development and characterization of a bioreactor for protein digestion. 1792 85

The aim of this work was to study the metabolic fate of 4-hydroxy- trans-2-nonenal (HNE) in human plasma, which represents the main vascular site of reactive carbonyl species (RCS) formation and where the main pro-atherogenic target proteins are formed. When HNE was spiked in human plasma, it rapidly disappeared (within 40 s) and no phase I metabolites were detected, suggesting that the main fate of HNE is due to an adduction mechanism. HNE consumption was then monitored in two plasma fractions: low molecular weight plasma protein fractions (<10 kDa; LMWF) and high molecular weight plasma protein fractions (>10 kDa; HMWF). HNE was almost stable in LMWF, while in HMWF it was consumed by almost 70% within 5 min. Proteomics identified albumin (HSA) as the main protein target, as further confirmed by a significantly reduced HNE quenching of dealbuminated plasma. LC-ESI-MS/MS analysis identified Cys34 and Lys199 as the most reactive adduction sites of HSA, through the formation of a Michael and Schiff base adducts, respectively. The rate constant of HNE trapping by albumin was 50.61 +/- 1.89 M (-1) s (-1) and that of Cys34 (29.37 M (-1) s (-1)) was 1 order of magnitude higher with respect to that of GSH (3.81 +/- 0.17 M (-1) s (-1)), as explained by molecular modeling studies. In conclusion, we suggest that albumin, through nucleophilic residues, and in particular Cys34, can act as an endogenous detoxifying agent of circulating RCS.
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PMID:Albumin is the main nucleophilic target of human plasma: a protective role against pro-atherogenic electrophilic reactive carbonyl species? 1832 89

We demonstrate here that pentagalloyl glucose (PGG), a main component of gallotannins, was an effective inhibitor of HSA and it exerted similar inhibitory potency to Aleppo tannin used in this study. The inhibition of HSA by PGG was found to be non-competitive and inhibitory constants of K(EI)=2.6 microM and K(ESI)=3.9 microM were determined from Lineweaver-Burk secondary plots. PGG as a model compound for gallotannins was selected to study the inhibitory mechanism and to characterize the interaction of HSA with this type of molecules. Surface plasmon resonance (SPR) binding experiments confirmed the direct interaction of HSA and PGG, and it also established similar binding of Aleppo tannin to HSA. Saturation transfer difference (STD) experiment by NMR clearly demonstrated the aromatic rings of PGG may be involved in the interaction suggesting a possible stacking with the aromatic side chains of HSA. The role of aromatic amino acids of HSA in PGG binding was reinforced by kinetic studies with the W58L and Y151M mutants of HSA: the replacement of the active site aromatic amino acids with aliphatic ones decreased the PGG inhibition dramatically, which justified the importance of these residues in the interaction.
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PMID:Evidence for pentagalloyl glucose binding to human salivary alpha-amylase through aromatic amino acid residues. 1903 68

The use of proteomics technology during the development of a new process for plasma protein separation was demonstrated. In a two-step process, the two most abundant proteins, HSA and IgG, were removed in a first step of anion-exchange chromatography using a gel with very high capacity. Subsequently, two fractions containing medium and low abundance proteins were re-chromatographed on a smaller column with the same type of gel. Collected fractions were separated by SDS-PAGE and 2-D electrophoresis, and excised proteins were digested with trypsin and identified by LC-ESI-MS/MS. This proteomic analysis proved to be a useful method for detection of low abundance therapeutic proteins and potential harmful contaminants during process development. Based on this method, low abundance therapeutic proteins, such as vitamin-K-dependent clotting factors and inhibitors, could be identified as present in target fractions after chromatographic separation. In addition, the tracking of potentially dangerous impurities and designing proper steps for their removal are important outcomes when developing, refining or controlling a new fractionation schema. For the purpose of in-process control, in-solution digestion of complete fractions followed by protein identification with LC-ESI-MS/MS was demonstrated as a rapid and simple alternative to the entire analysis including 1-D or 2-D electrophoretic steps.
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PMID:Proteomic analysis for process development and control of therapeutic protein separation from human plasma. 1929 37

HSA solutions account for 14% of the world market for plasma products. Albumin is indicated for reestablishing and maintaining circulatory volume in situations resulting from traumatic shock, surgery, or blood loss. Albumin is also used in extracorporeal liver support devices that perform blood dialysis against this protein. However, the protein composition of therapeutic albumin is only partially known. We performed an exhaustive analysis of albumin composition using a proteomic approach. Low abundance proteins and peptides in these samples were concentrated using a strong anion exchange resin. The absorbed material was eluted with a stepwise gradient of ammonium trifluoroacetate and the protein fraction was digested and analyzed by multidimensional liquid chromatography coupled to ESI-MS/MS using a linear ion trap. A total of 1219 peptides corresponding to 141 proteins different from albumin were identified with a false discovery rate <1%. Near 50% of these proteins have been described previously as forming part of the albuminome. Some of these proteins are proteases (kallikrein) or protease inhibitors (kininogen and SRPK1) or have relevant functions in cell surface adhesion (selectin, cadherins, and ICAMs) or in immunity and defense (molecules of the complement system and attractin). Characterization of these proteins and peptides is crucial in order to understand the therapeutic and possible deleterious effects of albumin therapies, in which this solution is infused to treat different pathological conditions.
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PMID:Characterization of peptides and proteins in commercial HSA solutions. 1988 58

The chemical diversity of secondary metabolites in medicinal plant makes it a huge challenge to isolate the bioactive compounds from herbal extracts, so quick recognition of the bioactive ones is of vital importance for improving the efficiency of isolation. In this study, a ligand fishing experiment based on human serum albumin functionalized magnetic nano-particles (HSA-MNPs) was performed to probe the bioactive components in a traditional Chinese medicinal plant, Dioscorea panthaica. The minor compounds fished out by HSA-MNPs were identified by electrospray ionization mass spectrometry (ESI-MS), and then separated from the extract of the whole plant by one or two steps of column chromatography under the guidance of ESI-MS. Four biologically active compounds, progenin II, progenin III, dioscin and gracillin, were isolated much faster than in the normal lengthy phytochemical procedure. The present study demonstrates that biological macromolecule (protein, enzyme, receptor, et al.) functionalized MNPs may serve as baits to recognize bioactive small molecules in complex herbal extracts. It is expected that a macromolecule functionalized MNPs-based ligand fishing experiment coupled with ESI-MS may accelerate the process of identification and isolation of bioactive components from medicinal plants, and thus benefit the speed of drug discovery.
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PMID:Rapid probe and isolation of bioactive compounds from Dioscorea panthaica using human serum albumin functionalized magnetic nano-particles (HSA-MNPs)-based ligand fishing coupled with electrospray ionization mass spectrometry. 2097 9

The chemical composition of herbal medicines is very complex, and their therapeutic effects are determined by multi-components with sophisticated synergistic and/or suppressive actions. Therefore, quality control of herbal medicines has been a formidable challenge. In this work, we describe a fast analytical method that can be used for quality assessment of herbal medicines. The method is based on ligand fishing using human-serum-albumin-functionalized magnetic nanoparticles (HSA-MNPs) and mass spectrometry. To demonstrate the applicability of the proposed method, eight samples of Dioscorea panthaica were analyzed. The sampled plants were of both wild and cultivated origins. They grew at different geographical locations and were harvested at different times. The ligands bound to HSA-MNPs were isolated from the plant extracts and detected by using direct infusion electrospray ionization mass spectrometry (DI-ESI-MS). Chemical identity has been confirmed for five of the ligands isolated. From more than 15 peaks in the ESI-MS spectrum, 11 common peaks were selected for calculating the correlation coefficient and cosine ratio. The values of correlation coefficient and cosine ratio were >0.9824 and >0.9988, respectively, for all the samples tested. The results indicated a high level of similarity among the eight D. panthaica samples. Compared with chromatographic fingerprint analysis, the proposed HSA-MNP-based DI-ESI-MS/MS approach was not only fast and easy to carry out but also biological-activity-oriented, promising a more effective data interpretation and thus reliable assessment conclusions.
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PMID:Ligand fishing with functionalized magnetic nanoparticles coupled with mass spectrometry for herbal medicine analysis: ligand fishing for herbal medicine analysis. 2108 27


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