The Reaction of Glutamic Acid with Acetic Anhydride and Pyridine<sup>1</sup>

King, John A.; McMillan, Freeman H.

doi:10.1021/ja01131a040

Cited by 28 publications

(12 citation statements)

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“…A definite identification of the imide formed would require some sensitive analysis technique to be applied to the dry samples without reexposure to water, perhaps MALDI-TOF using the silica support itself as a matrix. The synthesis of PyroGluDKP has previously been carried out in strongly dehydrating conditions . A yield of 60% was obtained in a 5:1 acetic anhydride: pyridine mixture at 110 °C, so that its obtention by a simple medium-temperature activation of Glu on silica would be interesting.…”

Section: Discussionmentioning

confidence: 99%

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Glutamic Acid Adsorption and Transformations on Silica

et al. 2011

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We report here on the adsorption and deposition of L-glutamic acid (Glu) on an amorphous silica and its subsequent thermal transformations. When adsorbed from aqueous solutions, Glu only has a low affinity for the silica surface but at high concentrations the adsorbed molecules serve as nuclei for the formation of small glutamic acid crystallites. As long as the Glu loading remains inferior to a saturation limit (about 0.5 molecule nm À2 ), the thermal behavior of adsorbed Glu is significantly different from that of bulk glutamic acid. Two successive condensation steps are observed upon mild thermal activation, and their products have been identified by a combination of techniques including thermogravimetry, in situ IR, solid-state NMR, and ESI-MS. The first step at about 120 °C is a lactam ring closure quantitatively yielding pyroglutamic acid in a first-order reaction. The second step, at 150 °C, probably results in the formation of a highly activated tricyclic imide, PyroGluDKP, and is easily reversible in the presence of water. These reactions have implications for prebiotic peptide formation and for synthetic chemistry.

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Section: Discussionmentioning

confidence: 99%

“…Finally, further condensation may proceed from the latter molecules to the formation of imide groups, yielding either the polycyclic compound sometimes called PyroGluDKP (1,7-diazatricyclo[7.3.0.0]dodecane-2,6,8,12-tetrone or 3,5,8,10-tetraketoperhydrodipyrrolo[ a , d ]pyrazine), or possibly a linear polyglutarimide.…”

Section: Introductionmentioning

confidence: 99%

Glutamic Acid Adsorption and Transformations on Silica

et al. 2011

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“…Sixteen out of 24 peptides had lower hydrophobicity index (HI) values (calculated based on SSRCalc algorithm) than the median HI (10.23) of total identified peptides in 0% DMSO (Figure S2D). , This result indicated that with 9% DMSO at the desalting step, we would lose possibility to detect hydrophilic peptides. However, in our method, the peptides of interest might be relatively hydrophobic because free amine groups are acetylated- d 3 , so the negative effect of DMSO might be limited for the N-blocked peptides.…”

Section: Resultsmentioning

confidence: 97%

“…For PSM validation in the plasma analysis, Percolator node in Proteome Discoverer 2.2 was utilized at PSM-level false discovery rate (FDR) of less than 1%. Peptides having N-terminal pyroglutamation were not included in further data analysis because this modification is suspected as in vitro modification. , In the plasma analysis, the peptide-level abundances were acquired based on the label free quantification (LFQ) method. For quantification, a combination of the Minora Feature Detector with default settings, Feature Mapper, and Precursor Ions Quantifier modules in Proteome Discoverer 2.2 was utilized.…”

Section: Materials and Methodsmentioning

confidence: 99%

tipNrich: A Tip-Based N-Terminal Proteome Enrichment Method

Lee

Kim

et al. 2021

Anal. Chem.

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The mass spectrometry-based analysis of protein post-translational modifications requires large amounts of sample, complicating the analysis of samples with limited amounts of proteins such as clinical biopsies. Here, we present a tip-based Nterminal analysis method, tipNrich. The entire procedure is processed in a single pipette tip to minimize sample loss, which is so highly optimized to analyze small amounts of proteins, even femtomole-scale of a single protein. With tipNrich, we investigated various single proteins purified from different organisms using a low-resolution mass spectrometer and identified several N-terminal peptides with different Nt-modifications such as ragged N-termini. Furthermore, we applied matrix-assisted laser desorption ionization time-of-flight mass spectrometry to our method for shortening the analysis time. Moreover, we showed that our method could be utilized in disease diagnosis as exemplified by the characterization of wild-type transthyretin amyloidosis patients compared to the healthy individuals based on N-terminome profiling. In summary, tipNrich will satisfy the need of identifying N-terminal peptides even with highly scarce amounts of proteins and of having faster processing time to check the quality of protein products or to characterize N-terminal proteoform-related diseases.

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“…Under such conditions, however, a stoichiometric amount of diol was found to be too small for dissolution of the diacid upon melting of the diol. Since DMDPP does not show a melting point and degrades at 211−213 °C, 13,14 further heating of the reaction until the diacid would melt was not a viable synthesis approach. This limitation was circumvented by synthesis of the dimethyl ester of DMDPP, which has a stable melt at 96−98 °C, allowing polymerization via transesterification.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Biobased Pyrazine-Containing Polyesters

Würdemann

Bernaerts

2020

ACS Sustainable Chem. Eng.

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A set of 12 first-in-class, biobased pyrazinecontaining polyesters was synthesized based on dimethylpyrazine dipropionic acid. These new diacid monomers were obtained from underutilized nitrogen-rich biomass. The polyester materials were synthesized via a two-step melt transesterification−polycondensation procedure with molecular weights between 12 300 and 47 500 g/mol and dispersities between 1.9 and 2.3. Six of the obtained polymers were amorphous and six were semi-crystalline. The thermal properties of the materials were studied; thermal degradation was found to take place at the monomer degradation temperature. The effect of methyl groups on the glass transition temperature was investigated, and the materials were found to behave mostly as aliphatic polyesters in this regard. The melting points of the methyl-substituted polyesters were found to be high and within the range of those of current high-performance polyesters. These materials are thus a welcome addition to current biobased polyesters.

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The Reaction of Glutamic Acid with Acetic Anhydride and Pyridine¹

Cited by 28 publications

References 1 publication

Glutamic Acid Adsorption and Transformations on Silica

Glutamic Acid Adsorption and Transformations on Silica

tipNrich: A Tip-Based N-Terminal Proteome Enrichment Method

Biobased Pyrazine-Containing Polyesters

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The Reaction of Glutamic Acid with Acetic Anhydride and Pyridine1

Cited by 28 publications

References 1 publication

Glutamic Acid Adsorption and Transformations on Silica

Glutamic Acid Adsorption and Transformations on Silica

tipNrich: A Tip-Based N-Terminal Proteome Enrichment Method

Biobased Pyrazine-Containing Polyesters

Contact Info

Product

Resources

About

The Reaction of Glutamic Acid with Acetic Anhydride and Pyridine¹