N-C<sub>α</sub> bond cleavage of the peptide backbone via hydrogen abstraction

Takayama, Mitsuo

doi:10.1016/s1044-0305(01)00289-6

Cited by 108 publications

(170 citation statements)

References 26 publications

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“…Hydrogen radicals formed by the matrix are at the origin of the formation of the c-and z-fragments [25][26][27], as depicted in a mechanism proposed by Takayama [25]. In the matrix crystals, hydrogen bonds are formed between the matrix and the analytes.…”

Section: Radical-induced Pathwaymentioning

confidence: 96%

MALDI In-Source Decay, from Sequencing to Imaging

Debois

Smargiasso

Demeure

et al. 2012

Topics in Current Chemistry

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Matrix-assisted laser desorption/ionization (MALDI) is now a mature method allowing the identification and, more challenging, the quantification of biopolymers (proteins, nucleic acids, glycans, etc). MALDI spectra show mostly intact singly charged ions. To obtain fragments, the activation of singly charged precursors is necessary, but not efficient above 3.5 kDa, thus making MALDI MS/MS difficult for large species. In-source decay (ISD) is a prompt fragmentation reaction that can be induced thermally or by radicals. As fragments are formed in the source, precursor ions cannot be selected; however, the technique is not limited by the mass of the analyzed compounds and pseudo MS3 can be performed on intense fragments. The discovery of new matrices that enhance the ISD yield, combined with the high sensitivity of MALDI mass spectrometers, and software development, opens new perspectives. We first review the mechanisms involved in the ISD processes, then discuss ISD applications like top-down sequencing and post-translational modifications (PTMs) studies, and finally review MALDI-ISD tissue imaging applications.

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Section: Radical-induced Pathwaymentioning

confidence: 96%

MALDI In-Source Decay, from Sequencing to Imaging

Debois

Smargiasso

Demeure

et al. 2012

Topics in Current Chemistry

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“…In previous studies, ISD of peptides/proteins has been proposed to proceed mainly through hydrogen transfer from matrix to analyte, producing c-and z-type ions via radicalinduced pathways [7,[11][12][13]. The thermochemical properties of matrices corroborated with the resulting ISD efficiencies, following a well-established rank for hydrogen-donating abilities: 1,5-DAN95-ASA92,5-DHB9SA9CHCA [11,12].…”

Section: Maldi-isd Of Pamam Dendrimers With Various Matricesmentioning

confidence: 72%

“…The relative abundances of a/x, b/y, and c/z-type ISD fragments, however, were lower than in ECD; less than 10 % of total S/E fragment abundance, but it was 60 %-85 % in the previous ECD experiment [19]. The observed a/x and c/z-type ISD fragments are very likely to be formed through hydrogen transfer from matrix to analyte via radical-induced pathways [7,[11][12][13].…”

Section: Fragmentation Characteristics Of Pamam Dendrimer Isdmentioning

confidence: 75%

“…In analyzing peptides/proteins, MALDI-ISD mainly forms c-and (z+2)-type ions, suggesting that a radical-induced pathway is deeply involved in the fragmentation mechanism [6,7], as found in electron capture dissociation (ECD) [8][9][10]. Previous studies revealed that intermolecular hydrogen transfer from matrix molecules to analytes and MALDI plume dynamics play important roles in the ISD of peptides/ proteins [3,7]. Thus, the ISD process appears to be matrixdependent, so the choice of matrix determines the fragmentation efficiency and pattern [5,[11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

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MALDI In-Source Decay Mass Spectrometry of Polyamidoamine Dendrimers

Lee

Han

et al. 2012

J. Am. Soc. Mass Spectrom.

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We report using MALDI-ISD (in-source decay) mass spectrometry (MS) to characterize highly branched synthetic polymers of polyamidoamine (PAMAM) dendrimer. This inherently monodisperse polymer possesses dendritic branches networked by tertiary amines and an amide functionality in each repeating unit. Among various ISD matrices examined, 2,5-DHB was the most efficient, yielding 33 fragments produced by single-or multiple-bond cleavages. Detailed analysis revealed that cleavages at tertiary amine sites (S-and E-type fragments) were the most pronounced, with various other cleavages around amide groups. The fragmentation mechanism appeared to follow the radical-induced dissociation pathway. In addition, the matrix dependence of PAMAM MALDI-ISD differed from that of peptides/proteins. The observed fragments provided rich structural information, which was suitable to characterize dendritic polymers.

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“…39–41 Takayama et al 42 described this mechanism as a hydrogen radical transfer from the matrix to the peptide bond carbonyl group, followed by radical ion rearrangements that predominantly yield c- and z + 2 ions. Based on this concept, MALDI-ISD has been used for protein and peptide sequencing, disulfide bond identification, localization of post-translation modifications (PTMs), and de novo sequencing of a 13.6 kDa protein.…”

Section: Introductionmentioning

confidence: 99%

Rapid, automated characterization of disulfide bond scrambling and IgG2 isoform determination

Resemann

Liu-Shin

Tremintin

et al. 2018

mAbs

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Human antibodies of the IgG2 subclass exhibit complex inter-chain disulfide bonding patterns that result in three structures, namely A, A/B, and B. In therapeutic applications, the distribution of disulfide isoforms is a critical product quality attribute because each configuration affects higher order structure, stability, isoelectric point, and antigen binding. The current standard for quantification of IgG2 disulfide isoform distribution is based on chromatographic or electrophoretic techniques that require additional characterization using mass spectrometry (MS)-based methods to confirm disulfide linkages. Detailed characterization of the IgG2 disulfide linkages often involve MS/MS approaches that include electrospray ionization or electron-transfer dissociation, and method optimization is often cumbersome due to the large size and heterogeneity of the disulfide-bonded peptides. As reported here, we developed a rapid LC-MALDI-TOF/TOF workflow that can both identify the IgG2 disulfide linkages and provide a semi-quantitative assessment of the distribution of the disulfide isoforms. We established signature disulfide-bonded IgG2 hinge peptides that correspond to the A, A/B, and B disulfide isoforms and can be applied to the fast classification of IgG2 isoforms in heterogeneous mixtures.

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N-C_α bond cleavage of the peptide backbone via hydrogen abstraction

Cited by 108 publications

References 26 publications

MALDI In-Source Decay, from Sequencing to Imaging

MALDI In-Source Decay, from Sequencing to Imaging

MALDI In-Source Decay Mass Spectrometry of Polyamidoamine Dendrimers

Rapid, automated characterization of disulfide bond scrambling and IgG2 isoform determination

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N-Cα bond cleavage of the peptide backbone via hydrogen abstraction

Cited by 108 publications

References 26 publications

MALDI In-Source Decay, from Sequencing to Imaging

MALDI In-Source Decay, from Sequencing to Imaging

MALDI In-Source Decay Mass Spectrometry of Polyamidoamine Dendrimers

Rapid, automated characterization of disulfide bond scrambling and IgG2 isoform determination

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Product

Resources

About

N-C_α bond cleavage of the peptide backbone via hydrogen abstraction