Synthesis of heptapeptides and analysis of sequence by tandem ion trap mass spectrometry

Jia, Chenxi; Qi, Wei; He, Zhimin; Yang, Haijun; Qiao, Bin

doi:10.2478/s11532-006-0004-6

Cited by 5 publications

(4 citation statements)

References 16 publications

(19 reference statements)

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“…This reaction was performed in a solution consisting of methylene chloride: DMF, 1:1, ( v / v ) in the presence of 4-dimethylaminopyridine (DMAP) and diisopropylcarbodiimide (DIC) obtaining TiO 2 @SiO 2 –(CH 2 ) 3 –NH–Gly–Fmoc. This procedure is used in peptide chemistry for the attachment of amino acids for resins calculations [ 46 ]. The Fmoc deprotection was performed using 20% ( v / v ) piperidine in DMF commonly used in the solid-phase peptide synthesis [ 47 ].…”

Section: Resultsmentioning

confidence: 99%

Efficient Method for the Concentration Determination of Fmoc Groups Incorporated in the Core-Shell Materials by Fmoc–Glycine

et al. 2020

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In this paper, we described the synthesis procedure of TiO2@SiO2 core-shell modified with 3-(aminopropyl)trimethoxysilane (APTMS). The chemical attachment of Fmoc–glycine (Fmoc–Gly–OH) at the surface of the core-shell structure was performed to determine the amount of active amino groups on the basis of the amount of Fmoc group calculation. We characterized nanostructures using various methods: transmission electron microscope (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) to confirm the modification effectiveness. The ultraviolet-visible spectroscopy (UV-vis) measurement was adopted for the quantitative determination of amino groups present on the TiO2@SiO2 core-shell surface by determination of Fmoc substitution. The nanomaterials were functionalized by Fmoc–Gly–OH and then the fluorenylmethyloxycarbonyl (Fmoc) group was cleaved using 20% (v/v) solution of piperidine in DMF. This reaction led to the formation of a dibenzofulvene–piperidine adduct enabling the estimation of free Fmoc groups by measurement the maximum absorption at 289 and 301 nm using UV-vis spectroscopy. The calculations of Fmoc loading on core-shell materials was performed using different molar absorption coefficient: 5800 and 6089 dm3 × mol−1 × cm−1 for λ = 289 nm and both 7800 and 8021 dm3 × mol−1 × cm−1 for λ = 301 nm. The obtained results indicate that amount of Fmoc groups present on TiO2@SiO2–(CH2)3–NH2 was calculated at 6 to 9 µmol/g. Furthermore, all measurements were compared with Fmoc–Gly–OH used as the model sample.

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Section: Resultsmentioning

confidence: 99%

Efficient Method for the Concentration Determination of Fmoc Groups Incorporated in the Core-Shell Materials by Fmoc–Glycine

et al. 2020

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“…The linear peptides were prepared manually using Wang resin as solid support and Fmoc methodology according to our previous report. 27 The cyclization of linear peptides was carried out in solution based on the following procedure. The linear peptides (0.10 mmol) were dissolved in DMF (7.8 × 10 -4 M) and the pH was adjusted to 8-9 by addition of N,N-diisopropylethylamine.…”

Section: Synthesis Of Cyclic Peptidesmentioning

confidence: 99%

Multi-Stage Collisionally-Activated Decomposition in an Ion Trap for Identification of Sequences, Structures and b_n → b_n-1 Fragmentation Pathways of Protonated Cyclic Peptides

Jia

et al. 2006

Eur J Mass Spectrom (Chichester)

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Cyclic penta-, hexa-and heptapeptides have been designed, synthesized and their fragmentations induced by multi-stage tandem mass spectrometry have been studied. Under low-energy collisionally-activated decomposition (CAD), the protonated cyclic peptides mainly dissociate via ring opening pathways and the corresponding b n → b n-1 pathways to form several sets of b ions as oxazolone rings (and b 1 ions as aziridinone rings). Through repeated observation of these b ions in multistep CAD experiments, accurate sequencing and headto-tail ring structure of cyclic peptides can be determined. The mistaken assignments of these b ions can be avoided by this sequencing method. Semi-empirical molecular orbital calculations have been utilized to provide insight into the proposed dissociation mechanism. In addition, for cyclic peptides that include an Asn residue, the nitrogen of the Asn side chain is observed to be preferentially protonated, which can induce a unique ring-opening pathway with a loss of ammonia that competes with the conventional ring opening pathway.

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“…The linear peptides were prepared manually using Wang resin as solid support following the Fmoc methodology as we reported previously [13]. The cyclizations of linear peptides were carried out in solution using the following procedure.…”

Section: Synthesis Of Axinastatinmentioning

confidence: 99%

Sequencing peptides by electrospray ion-trap mass spectrometry: A useful tool in synthesis of Axinastatin 3

Jia

et al. 2006

Open Chemistry

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Axinastatin 3 as a potential anticancer agent was synthesized by chemical methods. In an electrospray ion-trap mass spectrometer, using one stage of tandem mass spectrometry (MS/MS), the linear peptide intermediate was sequenced via the complementarities of y and b ions. Then, using multistep MS/MS (to MS 6 ), the cyclic peptide was sequenced through sequentially removing one amino acid residue in each stage of MS/MS. The difference of the fragmentation mechanisms and the sequencing approaches between them is discussed.

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Synthesis of heptapeptides and analysis of sequence by tandem ion trap mass spectrometry

Cited by 5 publications

References 16 publications

Efficient Method for the Concentration Determination of Fmoc Groups Incorporated in the Core-Shell Materials by Fmoc–Glycine

Efficient Method for the Concentration Determination of Fmoc Groups Incorporated in the Core-Shell Materials by Fmoc–Glycine

Multi-Stage Collisionally-Activated Decomposition in an Ion Trap for Identification of Sequences, Structures and b_n → b_n-1 Fragmentation Pathways of Protonated Cyclic Peptides

Sequencing peptides by electrospray ion-trap mass spectrometry: A useful tool in synthesis of Axinastatin 3

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Synthesis of heptapeptides and analysis of sequence by tandem ion trap mass spectrometry

Cited by 5 publications

References 16 publications

Efficient Method for the Concentration Determination of Fmoc Groups Incorporated in the Core-Shell Materials by Fmoc–Glycine

Efficient Method for the Concentration Determination of Fmoc Groups Incorporated in the Core-Shell Materials by Fmoc–Glycine

Multi-Stage Collisionally-Activated Decomposition in an Ion Trap for Identification of Sequences, Structures and bn → bn-1 Fragmentation Pathways of Protonated Cyclic Peptides

Sequencing peptides by electrospray ion-trap mass spectrometry: A useful tool in synthesis of Axinastatin 3

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Multi-Stage Collisionally-Activated Decomposition in an Ion Trap for Identification of Sequences, Structures and b_n → b_n-1 Fragmentation Pathways of Protonated Cyclic Peptides