Biochemistry of Protein-Isocyanate Interactions: A Comparison of the Effects of Aryl vs. Alkyl Isocyanates

Brown, William E.; Green, Allen H.; Cedel, Thomas E.; Cairns, Jennifer

doi:10.2307/3430269

Cited by 13 publications

(12 citation statements)

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“…On another hand, it is also known that the reaction of isocyanates with these functional groups competes with the hydrolysis to the corresponding amine and the release of carbon dioxide. It has been reported that the relative hydrolysis rates of aryl monoisocyanates are 5-1400-fold faster over alkyl monoisocyanates, depending also on the solvent chosen for the study (34). We now report our results on the reactivity, followed by 13 C NMR, of 13 C-labeled phenyl isocyanate 1 and p-tolyl isocyanate 2 toward nucleophilic amino acids in a semiorganic CD 3 CN/PBS (0.1 M; pH 7.4) medium.…”

Section: Discussionmentioning

confidence: 90%

Nuclear Magnetic Resonance Studies on Covalent Modification of Amino Acids Thiol and Amino Residues by Monofunctional Aryl ¹³C-Isocyanates, Models of Skin and Respiratory Sensitizers: Transformation of Thiocarbamates into Urea Adducts

Fleischel

Giménez‐Arnau

Lepoittevin

2009

Chem. Res. Toxicol.

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Exposure to aryl isocyanates, intermediates in the manufacture of polyurethanes, provokes lung sensitization and asthma but also occupational allergic contact dermatitis, sensitization occurring from a single accidental exposure. The initial step in the sensitization process is believed to be the covalent binding of the -N triple bond C triple bond O group with nucleophilic residues on proteins. While a wide knowledge exists on the reactivity of skin sensitizers toward amino acids, little is known about respiratory sensitizers such as aryl isocyanates. (13)C-Labeled monofunctional aryl isocyanates were synthesized, and their reactivities toward nucleophilic amino acids, GSH, and a model peptide were studied by (13)C and [(1)H-(13)C] NMR spectroscopy. An acetonitrile/buffer solution was used as a solvent to avoid the hampering of the follow up of the reactivity by the isocyanate hydrolysis competing reaction. The compounds reacted with thiol groups, through the formation of thiocarbamate bonds and with amino groups to form urea derivatives. The reactivity was confirmed with GSH, containing both free amino and thiol groups, and with a model peptide, particularly in the case of the reaction with lysine. The use of (13)C NMR to follow the aryl isocyanates reversible conjugation with thiol groups is also reported. Particularly, it is shown that thiocarbamate adducts can be converted into adducts of the urea kind by reaction with amino groups. These results confirmed the hypothesis by which thiol-containing peptides/proteins may act as carriers of isocyanates for possible reaction at a later time and/or place with other nucleophiles and confirmed the role of lysine as a good competing nucleophilic amino acid. The reactivity of aryl isocyanates with thiol and amino groups needs thus to be considered in their assigned sensitization processes.

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Section: Discussionmentioning

confidence: 90%

Nuclear Magnetic Resonance Studies on Covalent Modification of Amino Acids Thiol and Amino Residues by Monofunctional Aryl ¹³C-Isocyanates, Models of Skin and Respiratory Sensitizers: Transformation of Thiocarbamates into Urea Adducts

Fleischel

Giménez‐Arnau

Lepoittevin

2009

Chem. Res. Toxicol.

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“…Several studies have proven that NSCE derivatives react with ε-amino groups of proteins and sometimes with hydroxyl-containing amino acids too (33). Likewise, reaction of isocyanates with amino, thiol, hydroxyl, and/or imidazole groups within proteins is also possible (34). Thus, it cannot be excluded that such reactions might also occur with NSC peptides, which are at least partially converted in situ into isocyanate peptides.…”

Section: Resultsmentioning

confidence: 98%

Synthesis of Peptide−Protein Conjugates Using N-Succinimidyl Carbamate Chemistry

et al. 2010

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Peptide-protein conjugates are useful tools in different fields of research as, for instance, the development of vaccines and drugs or for studying biological mechanisms, to cite only few applications. N-Succinimidyl carbamate (NSC) chemistry has been scarcely used in this area. We show that unprotected peptides, featuring one lysine residue within their sequences, can be converted in good yield into NSC derivatives by reaction with disuccinimidylcarbonate (DSC). No hydrolysis of the NSC group was observed during RP-HPLC purification, lyophilization, or storage. NSC peptides reacted efficiently within minutes with lysozyme used as model protein. To illustrate usefulness of the method consisting of the synthesis of a peptide-protein conjugate of biological interest, a NSC peptide derived from a peptide substrate for tyrosylprotein sulfotransferase (TS) was synthesized and ligated to receptor-binding nontoxic B-subunit of Shiga toxin (STxB). Immunofluorescence studies showed the intracellular delivery of the TS-STxB conjugate and its ability to circulate to the Golgi as the native STxB protein. Moreover, we demonstrate that the TS label could be sulfated by tyrosylprotein sulfotransferases present in the Golgi. Thus, NSC chemistry permitted rapid synthesis of a peptide-protein conjugate worthwhile for studying the transport of proteins from the plasma membrane to the Golgi. The second part of this article describes a more general method for synthesizing peptide-protein conjugates without any limitation of the peptide sequence. The conjugates were assembled by combining NSC chemistry and alpha-oxo semicarbazone ligation. To this end, a glyoxylyl NSC peptide was synthesized and reacted with lysozyme. The glyoxylyl groups on the protein were then reacted with a semicarbazide peptide to produce the target peptide-protein conjugate. Both reactions, namely, urea bond formation and alpha-oxo semicarbazone ligation, were carried at pH 8.0 using a one-pot procedure.

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“…MIC has been shown to cause greater interaction with macromolecules than aryl isocyanates (Brown et al, 1987). Reversible conjugation of isocyanates with glutathione , which occurs both spontaneously and enzymatically, may have been the mechanism of distributing MIC molecules to different parts of the body and the reason behind its diffuse toxicity profile (Baillie and Slatter, 1991;Pearson et al, 1991).…”

Section: Reactions With Body Constituentsmentioning

confidence: 99%

Methyl Isocyanate

Varma¹,

Mulay²

2015

Handbook of Toxicology of Chemical Warfare Agents

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Biochemistry of Protein-Isocyanate Interactions: A Comparison of the Effects of Aryl vs. Alkyl Isocyanates

Cited by 13 publications

References 0 publications

Nuclear Magnetic Resonance Studies on Covalent Modification of Amino Acids Thiol and Amino Residues by Monofunctional Aryl ¹³C-Isocyanates, Models of Skin and Respiratory Sensitizers: Transformation of Thiocarbamates into Urea Adducts

Nuclear Magnetic Resonance Studies on Covalent Modification of Amino Acids Thiol and Amino Residues by Monofunctional Aryl ¹³C-Isocyanates, Models of Skin and Respiratory Sensitizers: Transformation of Thiocarbamates into Urea Adducts

Synthesis of Peptide−Protein Conjugates Using N-Succinimidyl Carbamate Chemistry

Methyl Isocyanate

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Biochemistry of Protein-Isocyanate Interactions: A Comparison of the Effects of Aryl vs. Alkyl Isocyanates

Cited by 13 publications

References 0 publications

Nuclear Magnetic Resonance Studies on Covalent Modification of Amino Acids Thiol and Amino Residues by Monofunctional Aryl 13C-Isocyanates, Models of Skin and Respiratory Sensitizers: Transformation of Thiocarbamates into Urea Adducts

Nuclear Magnetic Resonance Studies on Covalent Modification of Amino Acids Thiol and Amino Residues by Monofunctional Aryl 13C-Isocyanates, Models of Skin and Respiratory Sensitizers: Transformation of Thiocarbamates into Urea Adducts

Synthesis of Peptide−Protein Conjugates Using N-Succinimidyl Carbamate Chemistry

Methyl Isocyanate

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Nuclear Magnetic Resonance Studies on Covalent Modification of Amino Acids Thiol and Amino Residues by Monofunctional Aryl ¹³C-Isocyanates, Models of Skin and Respiratory Sensitizers: Transformation of Thiocarbamates into Urea Adducts

Nuclear Magnetic Resonance Studies on Covalent Modification of Amino Acids Thiol and Amino Residues by Monofunctional Aryl ¹³C-Isocyanates, Models of Skin and Respiratory Sensitizers: Transformation of Thiocarbamates into Urea Adducts