Tritium labelling of PACAP‐38 using a synthetic diiodinated precursor peptide

Pedersen, Martin Holst Friborg; Baun, Michael

doi:10.1002/jlcr.1941

Cited by 4 publications

(3 citation statements)

References 21 publications

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“…The peptides H-LQLQPFPQPELPYPQPELPYPQPELP YPQPQPF-OHY (33-mer) and H-LGQQQPFPPQQP YPQPQPF-OHY (19-mer), 98% pure (Schafer-N, Denmark), were 3 H-labeled in the underlined positions using diiodotyrosine (Y(3,5-I 2 )) iodinated peptides by standard technique [ 22 , 23 ]. They were dissolved in DMSO, mixed with 10% palladium on carbon catalyst, and subjected to 10 Ci tritium gas in a tritium manifold system (RC Tritec) for 2 h at room temperature, then purified by HPLC, and conserved by addition of 50 mM ascorbic acid.…”

Section: Methodsmentioning

confidence: 99%

Large Gliadin Peptides Detected in the Pancreas of NOD and Healthy Mice following Oral Administration

Bruun

Josefsen

Tanassi

et al. 2016

Journal of Diabetes Research

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Gluten promotes type 1 diabetes in nonobese diabetic (NOD) mice and likely also in humans. In NOD mice and in non-diabetes-prone mice, it induces inflammation in the pancreatic lymph nodes, suggesting that gluten can initiate inflammation locally. Further, gliadin fragments stimulate insulin secretion from beta cells directly. We hypothesized that gluten fragments may cross the intestinal barrier to be distributed to organs other than the gut. If present in pancreas, gliadin could interact directly with the immune system and the beta cells to initiate diabetes development. We orally and intravenously administered 33-mer and 19-mer gliadin peptide to NOD, BALB/c, and C57BL/6 mice and found that the peptides readily crossed the intestinal barrier in all strains. Several degradation products were found in the pancreas by mass spectroscopy. Notably, the exocrine pancreas incorporated large amounts of radioactive label shortly after administration of the peptides. The study demonstrates that, even in normal animals, large gliadin fragments can reach the pancreas. If applicable to humans, the increased gut permeability in prediabetes and type 1 diabetes patients could expose beta cells directly to gliadin fragments. Here they could initiate inflammation and induce beta cell stress and thus contribute to the development of type 1 diabetes.

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Section: Methodsmentioning

confidence: 99%

Large Gliadin Peptides Detected in the Pancreas of NOD and Healthy Mice following Oral Administration

Bruun

Josefsen

Tanassi

et al. 2016

Journal of Diabetes Research

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“…Halogenated aromatic amino acids or amino acids containing double or triple bonds are widely used in peptide synthesis to design peptide precursors. Subsequent metal-catalyzed halogen/tritium exchange 18 or reduction of the double/triple bond 19 with tritium gas leads to the desired 3 H-peptide. Derivatization of a native peptide by direct iodination with nonradioactive iodine ( 127 I) using sodium iodide and an oxidizing agent, such as iodogen or chloramine-T, also leads to a peptide precursor.…”

Section: Considerations For Tritiating Peptidesmentioning

confidence: 99%

Tritium Labeling of Neuromedin S by Conjugation with [³H]N-Succinimidyl Propionate

et al. 2023

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The human neuropeptide neuromedin S (NMS) consists of 33 amino acids. The introduction of tritium atoms into NMS has not been described so far. This represents a gap for using [ 3 H]NMS in radioreceptor binding assays or in tracking and monitoring their metabolic pathway. Two approaches for the incorporation of tritium into NMS were explored in this study: (1) halogenation at the His-18 residue followed by catalyzed iodine-127/tritium exchange and (2) conjugation of tritiated N -succinimidyl-[2,3- 3 H 3 ]propionate ([ 3 H]NSP) to at least one of the three available primary amines of amino acids Ile-1, Lys-15, and Lys-16 in the peptide sequence. Although iodination of histidine was achieved, subsequent iodine-127/deuterium exchange was unsuccessful. Derivatization at the three possible amino positions in the peptide using nonradioactive NSP resulted in a mixture of unconjugated NSM and 1- to 3-conjugations at different amino acids in the peptide sequence. Each labeling position in the mixture was assigned following detailed LC–MS/MS analysis. After separating the mixture, it was shown in an in vitro fluorometric imaging plate reader (FLIPR) and in a competitive binding assay that the propionyl-modified NMS derivatives were comparable to the unlabeled NMS, regardless of the degree of labeling and the labeling position(s). A molecular simulation with NMS in the binding pocket of the protein neuromedin U receptor 2 (NMUR 2 ) confirmed that the possible labeling positions are located outside the binding region of NMUR 2 . Tritium labeling was achieved at the N-terminal Ile-1 using [ 3 H]NSP in 7% yield with a radiochemical purity of >95% and a molar activity of 90 Ci/mmol. This approach provides access to tritiated NMS and enables new investigations to characterize NMS or corresponding NMS ligands.

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“…A tritritiomethyl Grignard reagent was used 44 to introduce tritium into a methylpentane cannabidiol. Other compounds recently labelled with tritium have included benzo[a]pyrene, 45 tryptamine and etodolac, 46 primulene, 47 thymidine, 48 the peptide PACAP-38 49 and a sigma-1 receptor, (+)-pentazocine. 50 Carbon ( 11 C & 14 C) Whilst it is interesting to report 51 the direct use of cyclotron produced [ 11 C] carbon dioxide as a tracer in fruit development, it is more usual for [ 11 C] methyl iodide to be prepared 52 which can then be used to introduce labelled methyl groups into a variety of compounds.…”

Section: Tritium ( 3 H)mentioning

confidence: 99%

Radiochemistry

Urch

2012

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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Tritium labelling of PACAP‐38 using a synthetic diiodinated precursor peptide

Cited by 4 publications

References 21 publications

Large Gliadin Peptides Detected in the Pancreas of NOD and Healthy Mice following Oral Administration

Large Gliadin Peptides Detected in the Pancreas of NOD and Healthy Mice following Oral Administration

Tritium Labeling of Neuromedin S by Conjugation with [³H]N-Succinimidyl Propionate

Radiochemistry

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Tritium labelling of PACAP‐38 using a synthetic diiodinated precursor peptide

Cited by 4 publications

References 21 publications

Large Gliadin Peptides Detected in the Pancreas of NOD and Healthy Mice following Oral Administration

Large Gliadin Peptides Detected in the Pancreas of NOD and Healthy Mice following Oral Administration

Tritium Labeling of Neuromedin S by Conjugation with [3H]N-Succinimidyl Propionate

Radiochemistry

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Tritium Labeling of Neuromedin S by Conjugation with [³H]N-Succinimidyl Propionate