Cornelia Koy, Ursula M Glocker, Bright D Danquah, Michael O Glocker
{"title":"Native and compactly folded <i>in-solution</i> conformers of pepsin are revealed and distinguished by mass spectrometric ITEM-TWO analyses of <i>gas-phase</i> pepstatin A - pepsin complex binding strength differences.","authors":"Cornelia Koy, Ursula M Glocker, Bright D Danquah, Michael O Glocker","doi":"10.1177/14690667231178999","DOIUrl":"10.1177/14690667231178999","url":null,"abstract":"<p><p>Pepsin, because of its optimal activity at low acidic pH, has gained importance in mass spectrometric proteome research as a readily available and easy-to-handle protease. Pepsin has also been study object of protein higher-order structure analyses, but questions about how to best investigate pepsin <i>in-solution</i> conformers still remain. We first determined dependencies of pepsin ion charge structures on solvent pH which indicated the <i>in-solution</i> existence of (a) natively folded pepsin (N) which by nanoESI-MS analysis gave rise to a narrow charge state distribution with an 11-fold protonated most intense ion signal, (b) unfolded pepsin (U) with a rather broad ion charge state distribution whose highest ion signal carried 25 protons, and (c) a compactly folded pepsin conformer (C) with a narrow charge structure and a 12-fold protonated ion signal in the center of its charge state envelope. Because pepsin is a protease, unfolded pepsin became its own substrate in solution at pH 6.6 since at this pH some portion of pepsin maintained a compact/native fold which displayed enzymatic activity. Subsequent mass spectrometric ITEM-TWO analyses of pepstatin A - pepsin complex dissociation reactions in the gas phase confirmed a very strong binding of pepstatin A by natively folded pepsin (N). ITEM-TWO further revealed the existence of two compactly folded <i>in-solution</i> pepsin conformers (C<sup>a</sup> and C<sup>b</sup>) which also were able to bind pepstatin A. Binding strengths of the respective compactly folded pepsin conformer-containing complexes could be determined and apparent gas phase complex dissociation constants and reaction enthalpies differentiated these from each other and from the pepstatin A - pepsin complex which had been formed from natively folded pepsin. Thus, ITEM-TWO turned out to be well suited to pinpoint <i>in-solution</i> pepsin conformers by interrogating quantitative traits of pepstatin A - pepsin complexes in the gas phase.</p>","PeriodicalId":12007,"journal":{"name":"European Journal of Mass Spectrometry","volume":" ","pages":"303-312"},"PeriodicalIF":1.3,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9553797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Matthias Bantle, Lanya van Tieghem, Wolfgang Weinmann, Marc Luginbühl
{"title":"Lyso-phosphatidylethanol detected by LC-MS/MS as a potential new marker for alcohol consumption.","authors":"Matthias Bantle, Lanya van Tieghem, Wolfgang Weinmann, Marc Luginbühl","doi":"10.1177/14690667231200143","DOIUrl":"10.1177/14690667231200143","url":null,"abstract":"<p><p>Alcohol biomarkers are able to reflect the degree of recent or long-term alcohol consumption, covering different windows of detection. Phosphatidylethanols (PEths) are an emerging group of direct alcohol biomarkers that are widely applied in clinical and forensic applications. Their quantification can provide insight into an individual's drinking behaviour. Here, we present a new sub-class of yet unknown PEth species, LysoPEths, which are structurally related to PEth, but miss one fatty acyl chain. LysoPEths can be either a degradation product of PEth or a product of transesterification of lyso-phosphatidylcholine (LysoPC) with ethanol. To set up an analytical method, LysoPEth 16:0 was synthesised from PC 16:0/18:1 and characterised by LC-MS/MS, using an enzymatic method: phospholipase D (PLD), followed by phospholipase A<sub>2</sub> (PLA<sub>2</sub>). Then, an LC-MS/MS method in MRM mode for LysoPEth 16:0 with additional LysoPEth species (LysoPEth 18:1, LysoPEth 18:2, and LysoPEth 20:4) and PEth 16:0/20:4 was developed. By incubation of freshly sampled venous blood of a teetotaller with ethanol at different concentrations, the formation of LysoPEth in parallel to PEth was investigated. With increasing ethanol concentrations, LysoPEth 16:0 was formed besides the known PEth species (PEth 16:0/18:1, PEth 16:0/18:2) for up to 72 h with LysoPEth concentrations being about three times lower than PEth concentrations. Storage of ethanol-free PEth-positive blood of an alcohol consumer at 37 °C showed that LysoPEth 16:0 concentrations increased, while PEth 16:0/18:1 concentrations decreased in the first 24 h for frozen/thawed blood, however not for freshly collected blood. Furthermore, LysoPEth 16:0 was detected in venous as well as lyophilised blood from clinical and forensic case work alongside with PEth 16:0/18:1, 16:0/18:2, and other PEth and LysoPEth species (PEth 16:0/20:4, LysoPEth 18:1, LysoPEth 18:2, and LysoPEth 20:4). LysoPEth 16:0 concentrations were found to be in linear correlation with PEth 16:0/18:1 (r<sup>2 </sup>= 0.75).</p>","PeriodicalId":12007,"journal":{"name":"European Journal of Mass Spectrometry","volume":" ","pages":"338-347"},"PeriodicalIF":1.3,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10244562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ji Eun Jung, Vanessa Cárdenas, Brîndușa Alina Petre
{"title":"Epitope identification of a Lys63 linkage ubiquitin antibody by mass spectrometric epitope excision and extraction approaches.","authors":"Ji Eun Jung, Vanessa Cárdenas, Brîndușa Alina Petre","doi":"10.1177/14690667231199012","DOIUrl":"10.1177/14690667231199012","url":null,"abstract":"<p><p>Ubiquitin, a conserved protein in eukaryotic cells, exists as a monomer or polyubiquitin chains known as isopeptide-linked polymers. These chains are attached to a substrate or other ubiquitin molecules through a covalent bond between the α-amino group of lysine in ubiquitin and glycine in the C-terminal of the subsequent ubiquitin unit. The choice of the specific lysine residue in ubiquitin for forming ubiquitin-ubiquitin chains determines its biochemical and biological function. A detailed chemical structure-function evaluation of the respective polyubiquitin chain is required. Interestingly, specific lysine linkage polyubiquitin chains become covalently bonded to many pathological inclusions seen in serious human disease states which appear to be resistant to normal degradation, so the interaction between polyubiquitin chains and ubiquitin antibodies is very useful. For example, the neurofibrillary tangles of Alzheimer's disease and the Lewy bodies seen in Parkinson's disease are heavily ubiquitinated and can be readily visualized using specific ubiquitin antibodies. This study utilized synthetic ubiquitin building block peptides that contained various lysine residues (K6, K11, K33, K48, and K63) linked to a Gly-Gly dipeptide, with the aim of exploring the recognition specificity of the Lys63-polyubiquitin antibody. The interaction studies between different ubiquitin building blocks and the specific Lys63-ubiquitin (K63-Ub) antibody were performed by affinity-mass spectrometry (Affinity-MS) and immunoblotting which enables direct protein identification from biological material with unprecedented selectivity. Affinity-MS and dot blot data proved the specific binding of the K63-Ub antibody to the ubiquitin peptides containing Lys6 or Lys63 residues. In epitope excision for mass spectrometric epitope identification, the ubiquitin building block with Lys63 residue bound to the immobilized K63-Ub antibody was proteolytically cleaved using pronase. The resulting epitope and non-epitope fractions were subjected to matrix-assisted laser desorption/ionization-time of flight analysis, revealing that the epitope is located within the sequence ubiquitin(60-66). Epitope extraction-MS consistently confirmed these findings.</p>","PeriodicalId":12007,"journal":{"name":"European Journal of Mass Spectrometry","volume":" ","pages":"348-358"},"PeriodicalIF":1.3,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10657902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mass spectrometry as a lens into molecular human nutrition and health.","authors":"Martin Kussmann","doi":"10.1177/14690667231193555","DOIUrl":"10.1177/14690667231193555","url":null,"abstract":"<p><p>Mass spectrometry (MS) has developed over the last decades into the most informative and versatile analytical technology in molecular and structural biology (). The platform enables discovery, identification, and characterisation of non-volatile biomolecules, such as proteins, peptides, DNA, RNA, nutrients, metabolites, and lipids at both speed and scale and can elucidate their interactions and effects. The versatility, robustness, and throughput have rendered MS a major research and development platform in molecular human health and biomedical science. More recently, MS has also been established as the central tool for 'Molecular Nutrition', enabling comprehensive and rapid identification and characterisation of macro- and micronutrients, bioactives, and other food compounds. 'Molecular Nutrition' thereby helps understand bioaccessibility, bioavailability, and bioefficacy of macro- and micronutrients and related health effects. Hence, MS provides a lens through which the fate of nutrients can be monitored along digestion via absorption to metabolism. This in turn provides the bioanalytical foundation for 'Personalised Nutrition' or 'Precision Nutrition' in which design and development of diets and nutritional products is tailored towards consumer and patient groups sharing similar genetic and environmental predisposition, health/disease conditions and lifestyles, and/or objectives of performance and wellbeing. The next level of integrated nutrition science is now being built as 'Systems Nutrition' where public and personal health data are correlated with life condition and lifestyle factors, to establish directional relationships between nutrition, lifestyle, environment, and health, eventually translating into science-based public and personal heath recommendations and actions. This account provides a condensed summary of the contributions of MS to a precise, quantitative, and comprehensive nutrition and health science and sketches an outlook on its future role in this fascinating and relevant field.</p>","PeriodicalId":12007,"journal":{"name":"European Journal of Mass Spectrometry","volume":" ","pages":"370-379"},"PeriodicalIF":1.3,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10016732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"In Memoriam of Michael Przybylski.","authors":"Michael O Glocker, Jürgen Grotemeyer","doi":"10.1177/14690667231211528","DOIUrl":"10.1177/14690667231211528","url":null,"abstract":"","PeriodicalId":12007,"journal":{"name":"European Journal of Mass Spectrometry","volume":"29 5-6","pages":"275"},"PeriodicalIF":1.3,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138298776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Top-down mass spectrometry for characterizing the low molecular weight proteome of canine osteosarcoma cell phenotypes.","authors":"Liping Yang, Stanislau Stanisheuski, Zifeng Song, Shay Bracha, Claudia S Maier","doi":"10.1177/14690667231202766","DOIUrl":"10.1177/14690667231202766","url":null,"abstract":"<p><p>Osteosarcoma (OS) is the most common primary malignant tumor of bone, which occupying about 20% of all bone cancers. To increase understanding of the biology of OS, we developed and evaluated a top-down mass spectrometry approach to detect, identify and quantify low molecular weight (MW) proteins (i.e., 1 kDa < MW < 30 kDa) in osteosarcoma cells. Top-down proteomic (TDP) data was acquired using reversed phase nano-liquid chromatography in conjunction with high-resolution mass spectrometry and resulted in the assignment of 328 proteins and 820 proteoforms or degradation products with high confidence. Eight post-translational modifications (PTMs) were identified in the present study, including N-terminal acetylation, lysine acetylation, succinylation, malonylation, serine/tyrosine phosphorylation, histidine methylation and N-acetylleucine. We confirmed that a truncated N-terminal proteoform lost 73 Da of mass through removal of the N-terminal Met (-131 Da), acetylation of the second amino acid (+42 Da), and Met oxidation (+16 Da). The results showed that the levels of proteoforms/biodegradable peptides correlated with the metastatic phenotypes of osteosarcoma cell lines. This study demonstrates the benefits of TDP for the characterization and relative quantification of proteoforms with relevance to OS biology and the potential of small molecular weight proteoforms to serve as a still underappreciated source of biomarkers.</p>","PeriodicalId":12007,"journal":{"name":"European Journal of Mass Spectrometry","volume":" ","pages":"313-325"},"PeriodicalIF":1.3,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10363179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Loredana Lupu, Wolfgang Kleinekofort, Nina Morgner
{"title":"Epitope characterization of proteins and aptamers with mass spectrometry.","authors":"Loredana Lupu, Wolfgang Kleinekofort, Nina Morgner","doi":"10.1177/14690667231208530","DOIUrl":"10.1177/14690667231208530","url":null,"abstract":"<p><p>The way in which professor Michael Przybylski has combined the spirit of research with entrepreneurship has set an example for any and all scientists. He has made significant achievements in the fields of mass spectrometry, biochemistry and medicine, and has initiated important technological developments in the area of protein analysis. Between 2016 and 2023 professor Przybylski's scientific focus shifted on protein interactions with emphasis on aptamer-protein and antibody-protein analysis. This review focuses on professor Przybylski's achievements in the last few years highlighting his impact on the scientific community, on his students and colleagues.</p>","PeriodicalId":12007,"journal":{"name":"European Journal of Mass Spectrometry","volume":" ","pages":"359-369"},"PeriodicalIF":1.3,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92153326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarah Trimpin, Ellen Inutan, Hope Coffinberger, Khoa Hoang, Frank Yenchick, James Wager-Miller, Milan Pophristic, Ken Mackie, Charles N McEwen
{"title":"Instrumentation development, improvement, simplification, and miniaturization: The multifunctional plate source for use in mass spectrometry.","authors":"Sarah Trimpin, Ellen Inutan, Hope Coffinberger, Khoa Hoang, Frank Yenchick, James Wager-Miller, Milan Pophristic, Ken Mackie, Charles N McEwen","doi":"10.1177/14690667231211486","DOIUrl":"https://doi.org/10.1177/14690667231211486","url":null,"abstract":"<p><p>In remembrance of Prof. Dr Przybylski, we are presenting a vision towards his beloved mass spectrometry (MS) and its far-reaching promises outside of the academic laboratory. Sub-atmospheric pressure (AP) ionization MS is well positioned to make a step-change in direct ionization, a concept that allows <i>sublimation/evaporation</i> ionization and mass analyses of volatile and nonvolatile molecules from clean or dirty samples, directly, accurately, sensitively, and in a straightforward manner that has the potential to expand the field of MS into unchartered application areas. Contrary to ambient ionization MS, ionization commences in the sub-AP region of the mass spectrometer, important for practical and safety reasons, and offers <i>inter alia</i>, simplicity, speed, sensitivity, and robustness directly from real-world samples without cleanup. The plate source concept, presented here, provides an easy to use, rapid, and direct sample introduction from AP into the sub-AP of a mass spectrometer. Utilizing sub-AP ionization MS based on the plate source concept, small to large molecules from various environments that would be deemed too dirty for some direct MS methods are demonstrated. The new source concept can be expanded to include multiple ionization methods using the same plate source \"front end\" without the need to vent the mass spectrometer between the different methods, thus allowing ionization of more compounds on the same mass spectrometer for which any one ionization method may be insufficient. Examples such as fentanyl, gamma-hydroxybutyric acid, clozapine, 1-propionyllysergic acid, hydrocodone angiotensin I and II, myoglobin, and carbonic anhydrase are included.</p>","PeriodicalId":12007,"journal":{"name":"European Journal of Mass Spectrometry","volume":"29 5-6","pages":"276-291"},"PeriodicalIF":1.3,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138298777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sensitive and rapid quantitation of dexamethasone in human plasma using liquid chromatography coupled with triple quadrupole mass spectrometer.","authors":"Naveen Kumar Dubey, Peeyush Jain","doi":"10.1177/14690667231194812","DOIUrl":"https://doi.org/10.1177/14690667231194812","url":null,"abstract":"<p><p>The aim of this paper was to develop, validate, and utilize a sensitive liquid chromatography-tandem mass spectrometry bioanalytical method for bioequivalence/clinical trial studies conducted in human plasma. To accomplish the target, a stable labeled internal standard, that is, dexamethasone D<sub>4</sub> was used as an internal standard to track and compensate the parent compound during processing, and extraction from plasma. The method involves a rapid liquid-liquid phase extraction from plasma, followed by reverse phase chromatography, and mass spectrometry detection, with a total run time of 3.5 min. The method was developed and validated from 2 to 600 ng/ml for dexamethasone. The mean recovery for dexamethasone was found to be 81.0%. The validated method enabled the analysis of dexamethasone in samples from clinical pharmacokinetic studies. The peak concentration of dexamethasone ranged between 253 to 281 ng/ml and 319 to 343 ng/ml, respectively, in fasted and fed conditions. The terminal half-life values for dexamethasone ranged between 3.5 to 8.2 h and 3.0 to 7.5 h, respectively.</p>","PeriodicalId":12007,"journal":{"name":"European Journal of Mass Spectrometry","volume":"29 4","pages":"240-247"},"PeriodicalIF":1.3,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10420691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Development and validation of a simple microwave-assisted digestion sample preparation technique for the estimation of aluminium and magnesium in a few pharmaceutical dosage forms by an inductively coupled-mass spectrometer (ICP-MS).","authors":"Ashish Kumar Pal, Raja Sundararajan","doi":"10.1177/14690667231184114","DOIUrl":"https://doi.org/10.1177/14690667231184114","url":null,"abstract":"<p><p><b>Rationale:</b> A simple, sensitive, reliable, validated, inductively coupled plasma mass spectrometric method for the determination of aluminium and magnesium using a simple common microwave-assisted digestion sample preparation technique for a few commonly used formulations was developed and validated according to International Conference on Harmonization Q3D and the United States Pharmacopeia general chapter <232> and <233>. The following pharmaceutical dosage forms were considered for estimation of aluminium and magnesium: Alumina, magnesia simethicone oral suspension, Alumina, magnesia simethicone chewable tablets, alumina and magnesia oral suspension, alumina and magnesium carbonate oral suspension. <b>Methods:</b> The methodology included optimizing a common microwave assisted digestion method, selecting the isotopes, choosing the measurement technique, and designating internal standards. The finalized microwave assisted procedure was a two-step program where in the first step the samples were ramped for 10 min to a temperature of 180 °C and hold for 5 min followed by ramping for 10 min to a temperature of 200 °C and hold for 10 min. Magnesium (<sup>24</sup>Mg) and aluminium (<sup>27</sup>Al) isotopes were finalized, internal standard assigned for both the isotopes was yttrium (<sup>89</sup>Y) with Helium (kinetic energy discrimination-KED) as the measuring mode. System suitability was run before initiating analysis to ensure that system performance was consistent. <b>Results:</b> Analytical validation parameters like specificity, linearity (from 25% to 200% of sample concentration), the detection limit and the limit of quantification were established. For all these dosage forms, the method's precision was demonstrated by analyzing the percentage relative standard deviation for six injections. Accuracy was established from 50% to 150% of instrument working concentration (J-levels) for aluminium and magnesium for all the formulations and was found to be within the range of 90-120%. <b>Conclusion:</b> This common analysis method, along with the common microwave-digestion technique applies to numerous types of matrices for a finished dosage form with aluminium and magnesium.</p>","PeriodicalId":12007,"journal":{"name":"European Journal of Mass Spectrometry","volume":"29 4","pages":"262-271"},"PeriodicalIF":1.3,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10054182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}