New observations on peptide bond formation using CDMT

Garrett, Christine E.; Jiang, Xinglong; Prasad, Kapa; Repič, Oljan

doi:10.1016/s0040-4039(02)00754-2

Cited by 49 publications

(36 citation statements)

References 4 publications

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“…Our experiment showed that DiLeu can be activated by DMTMM/NMM in DMF and time course study indicated this reaction reached equilibrium in an hour. Several reactions suggesting a two-step condensation by DMTMM were reported previously 42–44. Briefly, the acid moiety was first activated with DMTMM/NMM and followed by addition of amines to the reaction mixture.…”

Section: Resultsmentioning

confidence: 98%

N,N-Dimethyl Leucines as Novel Isobaric Tandem Mass Tags for Quantitative Proteomics and Peptidomics

et al. 2010

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Herein we describe the development and application of a set of novel N, N-dimethyl leucine (DiLeu) 4-plex isobaric tandem mass (MS2) tagging reagents with high quantitation efficacy and greatly reduced cost for neuropeptide and protein analysis. DiLeu reagents serve as attractive alternatives for isobaric tag for relative and absolute quantitation (iTRAQ) and tandem mass tags (TMTs) due to their synthetic simplicity, labeling efficiency and improved fragmentation efficiency. DiLeu reagent resembles the general structure of a tandem mass tag in that it contains an amine reactive group (triazine ester) targeting the N-terminus and ε-amino group of the lysine side-chain of a peptide, a balance group, and a reporter group. A mass shift of m/z 145.1 is observed for each incorporated label. Intense a1 reporter ions at m/z 115.1, 116.1, 117.1, and 118.1 are observed for all pooled samples upon MS2. All labeling reagents are readily synthesized from commercially available chemicals with greatly reduced cost. Labels 117 and 118 can be synthesized in one step and labels 115 and 116 can be synthesized in two steps. Both DiLeu and iTRAQ reagents show comparable protein sequence coverage (~43%) and quantitation accuracy (<15%) for tryptically digested protein samples. Furthermore, enhanced fragmentation of DiLeu labeling reagents offers greater confidence in protein identification and neuropeptide sequencing from complex neuroendocrine tissue extracts from a marine model organism, Callinectes sapidus.

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Section: Resultsmentioning

confidence: 98%

N,N-Dimethyl Leucines as Novel Isobaric Tandem Mass Tags for Quantitative Proteomics and Peptidomics

et al. 2010

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“…CH 3 CN (3.0 mL) was added followed by 4-methylmorpholine (NMM) (0.34 mL, 3.11 mmol) over 10 minutes. 79 The reaction mixture turned cloudy after NMM addition. The reaction stirred at 15 °C, under argon-balloon for 2 hours, it was then quenched with H 2 O (12 mL) and extracted with ethyl acetate (30 mL).…”

Section: Methodsmentioning

confidence: 99%

Tyrosine−Lipid Peroxide Adducts from Radical Termination: Para Coupling and Intramolecular Diels−Alder Cyclization

et al. 2010

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Free radical co-oxidation of polyunsaturated lipids with tyrosine or phenolic analogs of tyrosine gave rise to lipid peroxide-tyrosine (phenol) adducts in both aqueous micellar and organic solutions. The novel adducts were isolated and characterized by 1D and 2D NMR as well as by mass spectrometry. The spectral data suggest that the polyunsaturated lipid peroxyl radicals give stable peroxide coupling products exclusively at the para position of the tyrosyl (phenoxy) radicals. These adducts have characteristic 13C chemical shifts at 185 ppm due to the cross-conjugated carbonyl of the phenol-derived cyclohexadienone. The primary peroxide adducts subsequently undergo intramolecular Diels-Alder (IMDA) cyclization, affording a number of diastereomeric tricyclic adducts that have characteristic carbonyl 13C chemical shifts at ~198 ppm. All NMR HMBC and HSQC correlations support the structure assignment of the primary and Diels-Alder adducts, as does MS collision induced dissociation. Kinetic rate constants and activation parameters for the IMDA reaction were determined and the primary adducts were reduced with cuprous ion giving a phenol-derived 4-hydroxycyclohexa-2,5-dienone. No products from adduction of peroxyls at the phenolic ortho position were found either in the primary or the cuprous reduction product mixtures. These studies provide a framework for understanding the nature of lipid-protein adducts formed by peroxyl-tyrosyl radical-radical termination processes. Coupling of lipid peroxyl radicals with tyrosyl radicals leads to cyclohexenone and cyclohexadienone adducts which are of interest in and of themselves since, as electrophiles, they are likely targets for protein nucleophiles. One consequence of lipid peroxyl reactions with tyrosyls may therefore be protein-protein crosslinks via interprotein Michael adducts.

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“…Analytes TRs 4-6 were prepared from DNB-amino acids and propylamine in the presence of N-methylmorpholine and 2chloro-4,6-dimethoxy-1,3,5-triazine. 18 Racemic analytes TR 7 and TR 8 were prepared in two steps from N-Boc protected amino acids. 19,20 Analytes TR 9 and TR 10 were purchased from Aldrich, while the rest of the analytes were prepared previously in our laboratory.…”

Section: Chemicalsmentioning

confidence: 99%

Performance of brush‐type HPLC chiral stationary phases with tertiary amide in the connecting tether

2006

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The replacement of the N-H hydrogen of the secondary amide-tethered Pirkle-concept N-(3,5-dinitrobenzoyl)-L-leucine derived chiral stationary phase with various pi-basic or aliphatic groups improved the chiral discrimination ability of new chiral stationary phases, based on the leucine- or alanine-derived chiral selector, for the enantiomers of various racemic neutral analytes with amide functional groups. Retention times decreased while separation and resolution factors increased, thus proving the role of pi-donor aromatic unit as an electron-rich shield in the front of a silica surface. In general, chiral stationary phase (CSP) 5 with the 3,5-dimethylphenyl unit showed best performance, while CSP 3, with phenyl unit, and CSP 7, with 1-naphthyl unit in the tertiary amide connecting tether, were less efficient.

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New observations on peptide bond formation using CDMT

Cited by 49 publications

References 4 publications

N,N-Dimethyl Leucines as Novel Isobaric Tandem Mass Tags for Quantitative Proteomics and Peptidomics

N,N-Dimethyl Leucines as Novel Isobaric Tandem Mass Tags for Quantitative Proteomics and Peptidomics

Tyrosine−Lipid Peroxide Adducts from Radical Termination: Para Coupling and Intramolecular Diels−Alder Cyclization

Performance of brush‐type HPLC chiral stationary phases with tertiary amide in the connecting tether

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