Photolysis of Recombinant Human Insulin in the Solid State: Formation of a Dithiohemiacetal Product at the C-Terminal Disulfide Bond

Mozziconacci, Olivier; Haywood, Jessica; Gorman, Eric M.; Munson, Eric J.; Schöneich, Christian

doi:10.1007/s11095-011-0519-1

Cited by 14 publications

(8 citation statements)

References 51 publications

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“…Along with the Cys–Tyr cross-link, the photo-irradiation of insulin in solution generated a dithiohemiacetal cross-link between Cys A20 and Cys B19 [71]. Such photolytically generated dithiohemiacetal cross-links have also been identified and characterized for various disulfide-containing model peptides and proteins, including human and mouse growth hormone and monoclonal antibodies (see below).…”

Section: Insulinmentioning

confidence: 99%

“…In order to evaluate the propensity for HAT reactions in solid insulin formulations, we prepared amorphous, crystalline, and microcrystalline human insulin [71]. Photo-irradiation at λ = 253.7 nm yielded a dithiohemiacetal between Cys A20 and Cys B19 , as well as peptide products with reduced Cys at the Cys B7 and Cys B19 positions, as characterized by HPLC-MS/MS.…”

Section: Insulinmentioning

confidence: 99%

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Thiyl Radical Reactions in the Chemical Degradation of Pharmaceutical Proteins

Schöneich

2019

Molecules

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Free radical pathways play a major role in the degradation of protein pharmaceuticals. Inspired by biochemical reactions carried out by thiyl radicals in various enzymatic processes, this review focuses on the role of thiyl radicals in pharmaceutical protein degradation through hydrogen atom transfer, electron transfer, and addition reactions. These processes can lead to the epimerization of amino acids, as well as the formation of various cleavage products and cross-links. Examples are presented for human insulin, human and mouse growth hormone, and monoclonal antibodies.

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Section: Insulinmentioning

confidence: 99%

Section: Insulinmentioning

confidence: 99%

Thiyl Radical Reactions in the Chemical Degradation of Pharmaceutical Proteins

Schöneich

2019

Molecules

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“…The exact structure of the adduct species (i.e., whether this involves an S–O or S–C bond) remains to be resolved. In addition to this Tyr–Cys crosslink, a dithiohemiacetal [–C(SH)–S–C–] crosslink was also detected, involving Cys A20 and Cys B19 , on photolysis of human insulin in the solid state [ 121 ]. The proposed mechanism involves formation of two RS • from the disulfide, followed by disproportionation of the two radicals to give a thiol (RSH) and a thioaldehyde (–C=S), and then molecular addition of the thiol to the thioaldehyde.…”

Section: Types Of Crosslinks Detected Within and Between Proteins And Peptidesmentioning

confidence: 99%

Oxidative Crosslinking of Peptides and Proteins: Mechanisms of Formation, Detection, Characterization and Quantification

et al. 2021

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Covalent crosslinks within or between proteins play a key role in determining the structure and function of proteins. Some of these are formed intentionally by either enzymatic or molecular reactions and are critical to normal physiological function. Others are generated as a consequence of exposure to oxidants (radicals, excited states or two-electron species) and other endogenous or external stimuli, or as a result of the actions of a number of enzymes (e.g., oxidases and peroxidases). Increasing evidence indicates that the accumulation of unwanted crosslinks, as is seen in ageing and multiple pathologies, has adverse effects on biological function. In this article, we review the spectrum of crosslinks, both reducible and non-reducible, currently known to be formed on proteins; the mechanisms of their formation; and experimental approaches to the detection, identification and characterization of these species.

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“…Such products were, in fact, observed when thiyl radicals were generated in several model peptides [59, 60, 73, 74] and proteins [75], but, interestingly, also in iron regulatory protein 2 (IRP2), potentially as a result of iron-dependent degradation [76, 77]. Importantly, both the reactions of thiyl radicals of model peptides and Cys oxidation in IRP2 also reveal the conversion of Cys to Ala.…”

Section: Hydrogen Transfer Reactions Of Thiyl Radicalsmentioning

confidence: 99%

Thiyl radicals and induction of protein degradation

Schöneich

2015

Free Radical Research

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Thiyl radicals are important intermediates in the redox biology and chemistry of thiols. These radicals can react via hydrogen transfer with various C-H bonds in peptides and proteins, leading to the generation of carbon-centered radicals, and, potentially, to irreversible protein damage. This review summarizes quantitative information on reaction kinetics and product formation, and discusses the significance of these reactions for protein degradation induced by thiyl radical formation.

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Photolysis of Recombinant Human Insulin in the Solid State: Formation of a Dithiohemiacetal Product at the C-Terminal Disulfide Bond

Abstract: Dithiohemiacetals represent novel structures generated through the photochemical modification of disulfide bonds. This is the first time that such structure is identified during the photolysis of a protein in the solid state.

Cited by 14 publications

References 51 publications

Thiyl Radical Reactions in the Chemical Degradation of Pharmaceutical Proteins

Thiyl Radical Reactions in the Chemical Degradation of Pharmaceutical Proteins

Oxidative Crosslinking of Peptides and Proteins: Mechanisms of Formation, Detection, Characterization and Quantification

Thiyl radicals and induction of protein degradation

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