scholarly journals Conformational stability of six truncated cHMG1a proteins studied in their mixture by H/D exchange and electrospray ionization mass spectrometry.

2001 ◽  
Vol 48 (4) ◽  
pp. 1131-1136 ◽  
Author(s):  
I Petry ◽  
J R Wigniewski ◽  
Z Szewczuk
Keyword(s):  
Mass Spectrometry ◽  
Degradation Products ◽  
Conformational Stability ◽  
Biological Significance ◽  
High Mobility ◽  
Intact Protein ◽  
Ionization Mass ◽  
Hmg Proteins ◽  
Hmg Protein

The high mobility group (HMG) proteins are abundant non-histone components of eukaryotic chromatin. The presence of C-terminal acidic tails is a common feature of the majority of HMG proteins. Although the biological significance of the acidic domains is not clear, they are conferring conformational and metabolic stability to the proteins in vitro. Moreover, the length and net charge of the acidic tails affect the strength of HMG protein interaction with DNA. Synthesis of an insect HMG protein by standard recombinant technology in bacteria leads to a mixture of the intact protein (cHMG1a-(1-113) (I)) and a series of its degradation products truncated at the C tail: cHMG1a-(1-111) (II); cHMG1a-(1-110) (III); cHuMGla-(1-109) (IV); cHMG1a-(1-108) (V); cHMG1a-(1-107) (VI); cHMG1a-(1-106) (VII). The proteins differ from each other only by the number of amino-acid residues at the C-terminal tail. We used H/D exchange mass spectrometry to characterize the stability of the proteins directly in their mixture. The results show that the proteins I-V and VII have very similar conformations. The protein VI is less compact and exchanges its protons faster than the others. It may be concluded that the C-terminal tail influences the conformation of the cHMG1a protein and that individual residues in this part of the protein play a key role in its compactness.

scholarly journals Synthesis and Matrix Properties of α-Cyano-5-phenyl-2,4-pentadienic Acid (CPPA) for Intact Proteins Analysis by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 6054
Author(s):  
Antonio Monopoli ◽  
Angelo Nacci ◽  
Tommaso R. I. Cataldi ◽  
Cosima D. Calvano
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Protein Analysis ◽  
Ionization Mass Spectrometry ◽  
Intact Protein ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Desorption Ionization ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

The effectiveness of a synthesized matrix, α-cyano-5-phenyl-2,4-pentadienic acid (CPPA), for protein analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in complex samples such as foodstuff and bacterial extracts, is demonstrated. Ultraviolet (UV) absorption along with laser desorption/ionization mass spectrometry (LDI-MS) experiments were systematically conducted in positive ion mode under standard Nd:YLF laser excitation with the aim of characterizing the matrix in terms of wavelength absorption and proton affinity. Besides, the results for standard proteins revealed that CPPA significantly enhanced the protein signals, reduced the spot-to-spot variability and increased the spot homogeneity. The CPPA matrix was successful employed to investigate intact microorganisms, milk and seed extracts for protein profiling. Compared to conventional matrices such as sinapinic acid (SA), α-cyano-4-hydroxycinnamic acid (CHCA) and 4-chloro-α-cyanocinnamic acid (CClCA), CPPA exhibited better signal-to-noise (S/N) ratios and a uniform response for most examined proteins occurring in milk, hazelnut and in intact bacterial cells of E. coli. These findings not only provide a reactive proton transfer MALDI matrix with excellent reproducibility and sensitivity, but also contribute to extending the battery of useful matrices for intact protein analysis.

Biochemical markers for pregnancy in the spent culture medium of in vitro produced bovine embryos

2021 ◽  
Author(s):  
Gabriela de Oliveira Fernandes ◽  
Marcella Pecora Milazzotto ◽  
Andrei Antonioni Guedes Fidelis ◽  
Taynan Stonoga Kawamoto ◽  
Ligiane de Oliveira Leme ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Biochemical Markers ◽  
Culture Medium ◽  
Culture Media ◽  
Ionization Mass ◽  
Metabolic Profiles ◽  
Bovine Embryos ◽  
The Media

Abstract The present study aimed to identify biomarkers to assess the quality of in vitro produced (IVP) bovine embryos in the culture media. IVP embryos on Day (D) 5 of development were transferred to individual drops, where they were maintained for the last 48 h of culture. Thereafter, the medium was collected and the embryos were transferred to the recipients. After pregnancy diagnosis, the media were grouped into the pregnant and nonpregnant groups. The metabolic profiles of the media were analyzed via electrospray ionization mass spectrometry, and the concentrations of pyruvate, lactate, and glutamate were assessed using fluorimetry. The spectrometric profile revealed that the media from embryos from the pregnant group presented a higher signal intensity compared to that of the nonpregnant group; the ions 156.13 Da [M + H]+, 444.33 Da [M + H]+, and 305.97 Da [M + H]+ were identified as biomarkers. Spent culture medium from expanded blastocysts (Bx) that established pregnancy had a greater concentration of pyruvate (p = 0.0174) and lesser concentration of lactate (p = 0.042) than spent culture medium from Bx that did not establish pregnancy. Moreover, pyruvate in the culture media of Bx can predict pregnancy with 90.9% sensitivity and 75% specificity. In conclusion, we identified markers in the culture media that helped in assessing the most viable IVP embryos with a greater potential to establish pregnancy.

scholarly journals Multilevel characterization of antibody-ligand conjugates by CESI-MS

2020 ◽  
Vol 20 ◽  
Author(s):  
Bryan Fonslow ◽  
Gabor Jarvas ◽  
Marton Szigeti ◽  
Andras Guttman
Keyword(s):  
Mass Spectrometry ◽  
Capillary Electrophoresis ◽  
Peptide Mapping ◽  
Site Occupancy ◽  
Intact Protein ◽  
Ionization Mass ◽  
Antibody Drug Conjugates ◽  
Drug Conjugates ◽  
Antibody Drug

Aims: Demonstrating the capabilities of our new capillary electrophoresis – mass spectrometry method, which facilitates highly accurate relative quantitation of modification site occupancy of antibody-ligand (e.g., antibody-drug) conjugates. Background: Antibody-drug conjugates play important roles in medical discovery for imaging and therapeutic intervention. The localization and stoichiometry of the conjugation can affect the orientation, selectivity, specificity, and strength of molecular interactions, influencing biochemical function. Objective: To demonstrate the option to analyze the localization and stoichiometry of antibody-ligand conjugates by using essentially the same method at all levels including ligand infusion, peptide mapping, as well as reduced and intact protein analysis. Materials and Methods: Capillary electrophoresis coupled to electrospray ionization mass spectrometry was used to analyze the antibodyligand conjugates. Results: We identified three prevalent ligand conjugation sites with estimated stoichiometries of 73, 14, and 6% and an average ligand-antibody ratio of 1.37, illustrating the capabilities of CE-ESI-MS for rapid and efficient characterization of antibody-drug conjugates. Conclusion: The developed multilevel analytical method offers a comprehensive way to determine the localization and stoichiometry of antibody-drug conjugates for molecular medicinal applications. In addition, a significant advantage of the reported approach is that small, hydrophilic, unmodified peptides well separated from the neutrals, which is not common with other liquid phase separation methods such as LC.

scholarly journals Pharmacological perspectives from Brazilian Salvia officinalis (Lamiaceae): antioxidant, and antitumor in mammalian cells

2016 ◽  
Vol 88 (1) ◽  
pp. 281-292 ◽  
Author(s):  
CHARLENE S.C. GARCIA ◽  
CAROLINE MENTI ◽  
ANA PAULA F. LAMBERT ◽  
THIAGO BARCELLOS ◽  
SIDNEI MOURA ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mammalian Cells ◽  
Annexin V ◽  
The Body ◽  
Salvia Officinalis ◽  
Gas Chromatography Mass Spectrometry ◽  
Ionization Mass ◽  
Hek 293 ◽  
Salvia Officinalis L

ABSTRACT Salvia officinalis (Lamiaceae) has been used in south of Brazil as a diary homemade, in food condiment and tea-beverage used for the treatment of several disorders. The objective of this study was to characterize chemical compounds in the hydroalcoholic (ExtHS) and aqueous (ExtAS) extract from Salvia officinalis (L.) by gas chromatography-mass spectrometry (GC-MS) and by high-resolution electrospray ionization mass spectrometry (ESI-QTOF MS/MS), evaluate in vitro ability to scavenge the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+), catalase (CAT-like) and superoxide dismutase (SOD-like) activity, moreover cytotoxic by MTT assay, alterations on cell morphology by giemsa and apoptotic-induced mechanism for annexin V/propidium iodide. Chemical identification sage extracts revealed the presence of acids and phenolic compounds. In vitro antioxidant analysis for both extracts indicated promising activities. The cytotoxic assays using tumor (Hep-2, HeLa, A-549, HT-29 and A-375) and in non-tumor (HEK-293 and MRC-5), showed selectivity for tumor cell lines. Immunocytochemistry presenting a majority of tumor cells at late stages of the apoptotic process and necrosis. Given the results presented here, Brazilian Salvia officinalis (L.) used as condiment and tea, may protect the body against some disease, in particularly those where oxidative stress is involved, like neurodegenerative disorders, inflammation and cancer.

scholarly journals Isolation and Structure Determination of Echinochrome A Oxidative Degradation Products

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4778
Author(s):  
Natalia P. Mishchenko ◽  
Elena A. Vasileva ◽  
Andrey V. Gerasimenko ◽  
Valeriya P. Grigorchuk ◽  
Pavel S. Dmitrenok ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Degradation Products ◽  
Lethal Dose ◽  
Oxidative Degradation ◽  
Degradation Process ◽  
Oxidation Products ◽  
Chemical Mechanism ◽  
Ionization Mass ◽  
Echinochrome A ◽  
Esi Ms

Echinochrome A (Ech A, 1) is one of the main pigments of several sea urchin species and is registered in the Russian pharmacopeia as an active drug substance (Histochrome®), used in the fields of cardiology and ophthalmology. In this study, Ech A degradation products formed during oxidation by O2 in air-equilibrated aqueous solutions were identified, isolated, and structurally characterized. An HPLC method coupled with diode-array detection (DAD) and mass spectrometry (MS) was developed and validated to monitor the Ech A degradation process and identify the appearing compounds. Five primary oxidation products were detected and their structures were proposed on the basis of high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) as 7-ethyl-2,2,3,3,5,7,8-heptahydroxy-2,3-dihydro-1,4-naphthoquinone (2), 6-ethyl-5,7,8-trihydroxy-1,2,3,4-tetrahydronaphthalene-1,2,3,4-tetraone (3), 2,3-epoxy-7-ethyl-2,3-dihydro-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone (4), 2,3,4,5,7-pentahydroxy-6-ethylinden-1-one (5), and 2,2,4,5,7-pentahydroxy-6-ethylindane-1,3-dione (6). Three novel oxidation products were isolated, and NMR and HR-ESI-MS methods were used to establish their structures as 4-ethyl-3,5,6-trihydroxy-2-oxalobenzoic acid (7), 4-ethyl-2-formyl-3,5,6-trihydroxybenzoic acid (8), and 4-ethyl-2,3,5-trihydroxybenzoic acid (9). The known compound 3-ethyl-2,5-dihydroxy-1,4-benzoquinone (10) was isolated along with products 7–9. Compound 7 turned out to be unstable; its anhydro derivative 11 was obtained in two crystal forms, the structure of which was elucidated using X-ray crystallography as 7-ethyl-5,6-dihydroxy-2,3-dioxo-2,3-dihydrobenzofuran-4-carboxylic acid and named echinolactone. The chemical mechanism of Ech A oxidative degradation is proposed. The in silico toxicity of Ech A and its degradation products 2 and 7–10 were predicted using the ProTox-II webserver. The predicted median lethal dose (LD50) value for product 2 was 221 mg/kg, and, for products 7–10, it appeared to be much lower (≥2000 mg/kg). For Ech A, the predicted toxicity and mutagenicity differed from our experimental data.

scholarly journals Increased Glutathionyl Hemoglobin in Diabetes Mellitus and Hyperlipidemia Demonstrated by Liquid Chromatography/Electrospray Ionization-Mass Spectrometry

2000 ◽  
Vol 46 (1) ◽  
pp. 82-88 ◽  
Author(s):  
Toshimitsu Niwa ◽  
Chika Naito ◽  
Abdul Hassan Mohammed Mawjood ◽  
Kiyohiro Imai
Keyword(s):  
Diabetes Mellitus ◽  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Electrospray Ionization ◽  
Electrospray Ionization Mass Spectrometry ◽  
Healthy Subjects ◽  
Oxygen Affinity ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass

Abstract Background: Erythrocytes contain a large amount of glutathione (GSH), which protects cells from oxidative injury. The purpose of this study was to examine whether hemoglobin (Hb) is modified with glutathione by oxidation of the thiol groups in diabetes mellitus and hyperlipidemia, and to determine the oxygen affinity of glutathionyl Hb. Methods: Hb samples obtained from patients with type 2 diabetes, patients with hyperlipidemia, and healthy subjects were analyzed by liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS). Glutathionyl Hb was synthesized in vitro by incubating Hb with GSH. The oxygen affinity of glutathionyl Hb was determined by measuring its oxygen dissociation curve. Results: We first demonstrated that the concentration of glutathionyl Hbβ chains is markedly increased in the diabetic patients and hyperlipidemic patients compared with healthy subjects. The in vitro synthesis of glutathionyl Hb by incubation of Hb with GSH was enhanced by adding H2O2, a reactive oxygen species, into the incubation solution. The glutathionyl Hb prepared in vitro by incubating Hb with GSH showed a marked increase in oxygen affinity and a marked decrease in the Hill coefficient compared with Hb incubated without GSH. Conclusions: Glutathionyl Hb may be useful as a clinical marker of oxidative stress. The increased concentrations of glutathionyl Hb with high oxygen affinity and low cooperativity in diabetes and hyperlipidemia may lead to reduced tissue oxygen delivery.

scholarly journals Electrospray ionization mass spectrometry combined with the ultra high performance liquid chromatography in the analysis of in vitro formation of chlorophyll complexes with copper and zinc

2014 ◽  
Vol 79 (6) ◽  
pp. 689-706 ◽  
Author(s):  
Jelena Zvezdanovic ◽  
Sanja Petrovic ◽  
Dejan Markovic ◽  
Tatjana Andjelkovic ◽  
Darko Andjelkovic
Keyword(s):  
Mass Spectrometry ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Electrospray Ionization ◽  
Electrospray Ionization Mass Spectrometry ◽  
High Performance ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Central Type

The aim of this work was to give more accurate insight in the interaction of major photosynthesis pigment, chlorophyll (Chl), with copper (II) and zinc (II) in solution by flow injection analysis with electrospray ionization mass spectrometry (FIA-ESI-MS) method, as well as combined with ultra high performance liquid chromatography with DAD detection (UHPLC-DAD). These interactions may potentially, but not necessarily lead to formation of Cu-Chl and Zn-Chl complexes of two different types, which has a lot of - at least - disfunctional implications in plant world. The results based on analysis of full-scan and MS/MS spectra - with or without the UHPLC chromatograms - confirm formation of ?central type? Cu-Chl complex, and ?central type? Zn-Chl complex as well, along with a proof for formation of ?peripheral? Zn-Chl complex, the latter one originating from a very week coordinative interaction at the edge of Chl structure. The used techniques appeared to be an efficient and reliable tool for studying formation and stability of heavy metals complexes with chlorophyll, at least in vitro, with a considerable possibility for assessment of real bio-environmental behavior.

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