Effect of Conformation on the Photodegradation of Trp- And Cystine-Containing Cyclic Peptides: Octreotide and Somatostatin

Mozziconacci, Olivier; Schöneich, Christian

doi:10.1021/mp5003174

Cited by 19 publications

(19 citation statements)

References 78 publications

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“…Parallel to this transformation, 3-methylene-indolenine, obtained through fragmentation of the original Trp313 added to Lys317. Such transformations have recently been documented by us for the UV exposure of octreotide 41 and IgG1. 42 The structure of the product is displayed in Table 2.…”

Section: Resultsmentioning

confidence: 69%

“…42 Such cleavage leads to the release of a C-terminal amidated protein, and the formation of a glyoxal derivative. 41 The latter is a reactive intermediate in the Maillard reaction. 43 That is, the protein fragment with the glyoxal would possibly form crosslinks with nucleophiles.…”

Section: Resultsmentioning

confidence: 99%

“…Such transformation of Trp has been documented earlier during the exposure of IgG1 to UV light, and involves intermediary radical cation formation of Trp. 41 However, the transformation of Trp313 into Gly313 through mere reaction of Fc glycoforms with H 2 O 2 is difficult to rationalize. We, therefore, believe that traces of redox-active metals in the samples may catalyze the transformation of Trp313 into Gly313 by H 2 O 2 .…”

Section: Discussionmentioning

confidence: 99%

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Comparative Evaluation of the Chemical Stability of 4 Well-Defined Immunoglobulin G1-Fc Glycoforms

Mozziconacci

Okbazghi

et al. 2016

Journal of Pharmaceutical Sciences

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As part of a series of papers in this special issue evaluating model IgG1-Fc glycoforms for biosimilarity analysis, three well-defined IgG1-Fc glycoforms (High mannose-Fc, Man5-Fc, GlcNAc-Fc), and a non-glycosylated Fc protein (N297Q-Fc) were examined in this work to elucidate chemical degradation pathways. The four proteins underwent a combination of accelerated thermal stability studies, and four independent forced degradation studies (UV-light, metal-catalyzed oxidation, peroxyl radicals, and hydrogen peroxide) at pH 6.0. Our results highlight chemical degradations at Asn315, Met428, Trp277, and Trp313. A cross-comparison of the different Fc glycoforms, stress conditions, and the observed chemical reactions revealed that both the deamidation of Asn315 and the transformation of Trp277 into glycine hydroperoxide were glycan-dependent during incubation for three months at 40°C. Our data will show that not only different glycans affect chemical degradation differently, but also do lead to different impurity profiles, which can affect chemical degradation.

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Section: Resultsmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Comparative Evaluation of the Chemical Stability of 4 Well-Defined Immunoglobulin G1-Fc Glycoforms

Mozziconacci

Okbazghi

et al. 2016

Journal of Pharmaceutical Sciences

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“…This result is consistent with a photo‐induced electron transfer from NATA to GSSG, resulting in the formation of 3‐MEI and GSH. More detailed mechanistic studies on the photo‐induced fragmentation of Trp were performed with two peptides, somatostatin and octreotide, both of which contain Trp and a disulfide bond . Here, photo‐induced electron transfer is expected to lead to the intermediary reduction of the carbonyl function of the peptide bond C‐terminal of the Trp residue, followed by electron transfer to the disulfide bond.…”

Section: Side Chain Cleavage Of Trp In Peptides and Proteinsmentioning

confidence: 99%

“…With reference to light‐induced Trp modification, this review will present an example, where forced degradation studies of octreotide identified a specific, novel degradation pathway (cf. Trp side chain cleavage), which was subsequently confirmed to proceed under exposure to ambient light . Forced degradation (including thermal forced degradation) has also become an important tool for biosimilar analysis .…”

Section: Introductionmentioning

confidence: 96%

Novel chemical degradation pathways of proteins mediated by tryptophan oxidation: tryptophan side chain fragmentation

Schöneich

2017

Journal of Pharmacy and Pharmacology

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Objectives This minireview focuses on novel degradation pathways of proteins in solution via intermediary tryptophan (Trp) radical cations, which are generated via photo-induced electron transfer to suitable acceptors such as disulfide bonds. Methods Gas-phase mass spectrometry studies had indicated the potential for Trp radical cations to fragment via release of 3-methylene-3H-indol-1-ium from the side chain. HPLC-MS/MS analysis demonstrates that analogous fragmentation reactions occur during the exposure of peptides and proteins to light or accelerated stability testing. Key findings The light exposure of selected peptides and monoclonal antibodies leads to the conversion of Trp to glycine (Gly) or glycine hydroperoxide (GlyOOH), where GlyOOH could be reduced to hydroxyglycine, which undergoes subsequent cleavage. Product formation is consistent with C a -C b fragmentation of intermediary Trp radical cations. For the peptide octreotide and specific glycoforms of IgG1 Fc domains, Trp side chain cleavage in aqueous solution is indicated by the formation of 3-methyleneindolenine (3-MEI), which adds to nucleophilic side chains, for example to Lys residues adjacent to the original Trp residues. Conclusions Trp side chain cleavage leads to novel reaction products on specific peptide and protein sequences, which may have consequences for potency and immunogenicity.

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Characterization by LC–MS/MS of oxidized products identified in synthetic peptide somatostatin and cetrorelix submitted to forced oxidative stress by hydrogen peroxide: Two case studies

Datola¹,

Pistacchio²,

Simone³

et al. 2023

J Mass Spectrom

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In a broader scenario, the forced degradation studies provided by the ICH guidelines for Q1A, Q1B, and Q2B degradation studies allow to know the CQA of the molecule used as a drug product, to determine the appropriate analytical methods, excipients, and storage conditions ensuring the quality of the drug, its efficacy, and patient safety. In this study, we focused our attention on understanding how oxidative stress is performed by H 2 O 2 -impacted small synthetic peptides that do not contain residues susceptible to oxidation such as methionine. Among the amino acids susceptible to oxidation, methionine is the most reactive and depending on the structure of the protein where it is exposed, it tends to oxidize by converting into methionine sulfone or methionine sulfoxide by oxidation of its sulfur atom. Scouting experiments obtained by forced oxidative stress conditions are presented on two small synthetic peptides that do not contain any methionine residues spiked with different amounts of H 2 O 2 , and they are analyzed by LC-MS/MS. Less frequent oxidation products than those commonly observed on proteins/peptides-containing methionine have been characterized on both peptides. The study demonstrated that somatostatin, by means of one residue of tryptophan on the molecule, can generate traces of several oxidized products detected by UPLC-MS. Furthermore, even at a negligible level, oxidation on tyrosine and proline in cetrorelix that does not contain methionine nor tryptophan has been detected by UHPLC-MS/MS. Identification and quantification of oxidized species were achieved by high-resolution MS and MS/MS experiments. Thus, FDSs undoubtedly aid the evaluation of the CQAs as an important component of the characterization package as recommended by HAs and ICH, facilitating the understanding of unforeseen features of the studied molecule used as drugs.

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Effect of Conformation on the Photodegradation of Trp- And Cystine-Containing Cyclic Peptides: Octreotide and Somatostatin

Cited by 19 publications

References 78 publications

Comparative Evaluation of the Chemical Stability of 4 Well-Defined Immunoglobulin G1-Fc Glycoforms

Comparative Evaluation of the Chemical Stability of 4 Well-Defined Immunoglobulin G1-Fc Glycoforms

Novel chemical degradation pathways of proteins mediated by tryptophan oxidation: tryptophan side chain fragmentation

Characterization by LC–MS/MS of oxidized products identified in synthetic peptide somatostatin and cetrorelix submitted to forced oxidative stress by hydrogen peroxide: Two case studies

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