Absolute and Accurate Quantification of Protein Phosphorylation by Using an Elemental Phosphorus Standard and Element Mass Spectrometry

2007 ◽  
Vol 46 (4) ◽  
pp. 569-571 ◽  
Author(s):  
A. Pereira Navaza ◽  
J. Ruiz Encinar ◽  
A. Sanz-Medel
Keyword(s):  
Mass Spectrometry ◽  
Protein Phosphorylation ◽  
Elemental Phosphorus ◽  
Accurate Quantification

scholarly journals Characterization and Quantification of Selenoprotein P: Challenges to Mass Spectrometry

2021 ◽  
Vol 22 (12) ◽  
pp. 6283
Author(s):  
Jérémy Lamarche ◽  
Luisa Ronga ◽  
Joanna Szpunar ◽  
Ryszard Lobinski
Keyword(s):  
Mass Spectrometry ◽  
State Of The Art ◽  
Animal Health ◽  
Primary Standard ◽  
Selenoprotein P ◽  
Primary Standards ◽  
Analytical Approaches ◽  
Careful Investigation ◽  
Accurate Quantification

Selenoprotein P (SELENOP) is an emerging marker of the nutritional status of selenium and of various diseases, however, its chemical characteristics still need to be investigated and methods for its accurate quantitation improved. SELENOP is unique among selenoproteins, as it contains multiple genetically encoded SeCys residues, whereas all the other characterized selenoproteins contain just one. SELENOP occurs in the form of multiple isoforms, truncated species and post-translationally modified variants which are relatively poorly characterized. The accurate quantification of SELENOP is contingent on the availability of specific primary standards and reference methods. Before recombinant SELENOP becomes available to be used as a primary standard, careful investigation of the characteristics of the SELENOP measured by electrospray MS and strict control of the recoveries at the various steps of the analytical procedures are strongly recommended. This review critically discusses the state-of-the-art of analytical approaches to the characterization and quantification of SELENOP. While immunoassays remain the standard for the determination of human and animal health status, because of their speed and simplicity, mass spectrometry techniques offer many attractive and complementary features that are highlighted and critically evaluated.

A Method for the Accurate Quantification of Gas Streams by Online Mass Spectrometry

2021 ◽  
Author(s):  
Edwing Alexander Velasco-Rozo ◽  
Luz Marina Ballesteros-Rueda ◽  
Víctor Gabriel Baldovino-Medrano
Keyword(s):  
Mass Spectrometry ◽  
Gas Streams ◽  
Accurate Quantification

Analysis of Protein Phosphorylation by a Combination of Elastase Digestion and Neutral Loss Tandem Mass Spectrometry

2001 ◽  
Vol 73 (2) ◽  
pp. 170-176 ◽  
Author(s):  
Andreas Schlosser ◽  
Ruediger Pipkorn ◽  
Dirk Bossemeyer ◽  
Wolf D. Lehmann
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Protein Phosphorylation ◽  
Neutral Loss ◽  
Tandem Mass

scholarly journals Extensive non-canonical phosphorylation in human cells revealed using strong-anion exchange-mediated phosphoproteomics

2017 ◽  
Author(s):  
Gemma Hardman ◽  
Simon Perkins ◽  
Zheng Ruan ◽  
Natarajan Kannan ◽  
Philip Brownridge ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Protein Phosphorylation ◽  
Anion Exchange ◽  
Human Cell ◽  
Cell Biology ◽  
Human Cells ◽  
Phosphopeptide Enrichment ◽  
Cell Extracts ◽  
Strong Anion Exchange ◽  
Acid Labile

Protein phosphorylation is a ubiquitous post-translational modification (PTM) that regulates all aspects of life. To date, investigation of human cell signalling has focussed on canonical phosphorylation of serine (Ser), threonine (Thr) and tyrosine (Tyr) residues. However, mounting evidence suggests that phosphorylation of histidine also plays a central role in regulating cell biology. Phosphoproteomics workflows rely on acidic conditions for phosphopeptide enrichment, which are incompatible with the analysis of acid-labile phosphorylation such as histidine. Consequently, the extent of non-canonical phosphorylation is likely to be under-estimated. We report an Unbiased Phosphopeptide enrichment strategy based on Strong Anion Exchange (SAX) chromatography (UPAX), which permits enrichment of acid-labile phosphopeptides for characterisation by mass spectrometry. Using this approach, we identify extensive and positional phosphorylation patterns on histidine, arginine, lysine, aspartate and glutamate in human cell extracts, including 310 phosphohistidine and >1000 phospholysine sites of protein modification. Remarkably, the extent of phosphorylation on individual non-canonical residues vastly exceeds that of basal phosphotyrosine. Our study reveals the previously unappreciated diversity of protein phosphorylation in human cells, and opens up avenues for exploring roles of acid-labile phosphorylation in any proteome using mass spectrometry.

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