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Chemistry of Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Phenol (183) and related materials, such as guaiacol (188), were once isolated from coal tar, but the bulk of their supply is currently produced from benzene via cumene as shown in Figure 6.31. The use of these intermediates to produce shikimates is shown in Figure 6.32. In principle, anethole (53) and estragole (methyl chavicol) (52) are available from phenol, but in practice, the demand is met by extraction from turpentine. Carboxylation of phenol gives salicylic acid (38) and hence serves as a source for the various salicylate esters. Formylation of phenol by formaldehyde, in the presence of a suitable catalyst, has now replaced the Reimer–Tiemann reaction as a route to hydroxybenzaldehydes. The initial products are saligenin (189) and p-hydroxybenzyl alcohol (190), which can be oxidized to salicylaldehyde (191) and p-hydroxybenzaldehyde (192), respectively. Condensation of salicylaldehyde with acetic acid/acetic anhydride gives coumarin (50) and O-alkylation of p-hydroxybenzaldehyde gives anisaldehyde (44). As mentioned earlier, oxidation of phenol provides a route to catechol (184) and guaiacol (188). The latter is a precursor for vanillin, and catechol also provides a route to heliotropin (61) via methylenedioxybenzene (193).
11C, 13N, and 15O Tracers
Published in Garimella V. S. Rayudu, Lelio G. Colombetti, Radiotracers for Medical Applications, 2019
Roy S. Tilbury, Alan S. Gelbard
11C-Formaldehyde has been used as a precursor in the enzymatic syntheses of 11C-thymidine and thymidylic acid.12, 55 It has also been used in reductive formylation reactions to produce 11C-labeled Imipramine, chlorpromazine, and nicotine.16 Straatman and Welch56 have developed a general method for labeling proteins with carbon-11 by reductive formylation. Such compounds as albumin, fibrinogen, ovine luteinizing hormone as well as the putrescine analog N-methyl-11C-1,4 diaminobutane have been labeled in this manner. 11C-Methyl iodide has been the methylating agent to label 11C-diazepam and 11C-caffeine, as well as 11C-L-methionine.16
Peptide Structure and Analysis
Published in Marco Chinol, Giovanni Paganelli, Radionuclide Peptide Cancer Therapy, 2016
Carlo Pedone, Giancarlo Morelli, Diego Tesauro, Michele Saviano
Chemical modification of the N-terminus of a peptide is often necessary to accomplish a variety of objectives. First, it can be useful as a device for simplifying the synthesis of difficult sequences; second, it can assist the purification of synthesized peptide; third, it can provide a useful tag by which to identify the peptide. Finally, peptides bearing a chemically modified N-terminus are not recognized by aminopeptidases, and therefore exhibit a longer half-life in vivo. Examples of N-terminus modifications are: formylation, acetylation, tert-butoxycarbonylation, and pyroglutammic formation. Moreover, most of the non-amino acid molecules, such as biotin, PEG, or fatty acids, are attached to a peptide using the N-terminus position. In fact, solid phase methodologies can be easy applied by reacting a carboxylic moiety of the non-amino acid molecule with the N-terminus of the peptide present on the solid support.
Formyl peptide receptor-1 (FPR1) represses intestinal oncogenesis
Published in OncoImmunology, 2023
Julie Le Naour, Léa Montégut, Yuhong Pan, Sarah Adriana Scuderi, Pierre Cordier, Adrien Joseph, Allan Sauvat, Valerio Iebba, Juliette Paillet, Gladys Ferrere, Ludivine Brechard, Claire Mulot, Grégory Dubourg, Laurence Zitvogel, Jonathan G. Pol, Erika Vacchelli, Pierre-Laurent Puig, Guido Kroemer
Formyl peptide receptors (FPRs) are pattern recognition receptors known to play important roles in diverse physiological processes, including host defense and inflammation.5 FPRs recognize peptides bearing a particular post-translational modification, namely N-formylation, that is only catalyzed by enzymes present in bacteria and in mitochondria. Hence, these N-formylated peptides consist of microbial pathogen-associated molecular patterns (MAMPs) or danger-associated molecular patterns (DAMPs) derived from dying cells spilling mitochondrial content.6,7 Furthermore, FPR1 recognizes non-formylated proteins such as (i) cathepsin G,8 (ii) family with sequence similarity 19 (chemokine (C–C motif)-like), member A4 (FAM19A4),9 and (iii) annexin A1 (ANXA1) that is released from the cytosolic compartment of dying and dead cells, hence constituting yet another DAMP.7,10
No impact of cancer and plague-relevant FPR1 polymorphisms on COVID-19
Published in OncoImmunology, 2020
Adriana Petrazzuolo, Julie Le Naour, Erika Vacchelli, Pascale Gaussem, Syrine Ellouze, Georges Jourdi, Eric Solary, Michaela Fontenay, David M. Smadja, Guido Kroemer
Formyl peptide receptor 1 (FPR1) is a pattern-recognition receptor (PRR)10 that is mostly expressed by myeloid cells including granulocytes, macrophages, and dendritic cells.11 Like other PRRs, FPR1 recognizes pathogen-associated molecular patterns (PAMPs), which are microbial structures, and danger-associated molecular patterns (DAMPs), which are host molecules displayed on, or released by, stressed and dying cells.12–15 As its name indicates, FPR1 recognizes formylated peptides, mostly peptides from bacteria that have undergone a prokaryote-specific post-translation protein modification called formylation.12 However, formylated peptides are also generated by mitochondria (which, in evolutionary terms, are relics of prokaryotes incorporated into the eukaryotic proto-organism).16,17 Moreover, FPR1 interacts with other endogenous ligands including annexin A1 (ANXA1), a ubiquitous protein contained in the cytosol of all nucleated cells that leak into the extracellular space when cells die.18–23 Thus, FPR1 plays a major role in the response to pathogens as well as in the regulation of immune and inflammatory responses.24
The NISTmAb tryptic peptide spectral library for monoclonal antibody characterization
Published in mAbs, 2018
Qian Dong, Yuxue Liang, Xinjian Yan, Sanford P. Markey, Yuri A. Mirokhin, Dmitrii V. Tchekhovskoi, Tallat H. Bukhari, Stephen E. Stein
We illustrate two examples of spectra rejected using these rules. The first rejected identification is shown in Figure 9A. In this example, a spectrum was initially identified as non-alkylated formylSCDhexKTHTCPPCPAPELLGGPSVFLFPPKPK (heavy chain 222–251) at m/z 839.1618, which is within 4 ppm of its theoretical value at charge state 4+. This false identification exhibits a combination of uncommon features: 1) misalkylation of all three cysteine residues, 2) N-terminal formylation, and 3) glycation of lysine. In other respects, it satisfied criteria for acceptance. We determined that this case might be better explained by the unintended sampling of the 13C isotope of a tryptic peptide, specifically the mono-oxidized heavy chain 222–251 peptide. Reexamination of the raw data justified the latter explanation. The second example is the rejected false identification of the triply-charged, modified light chain N-terminal peptide, as DdehydratedIcation:2Ca[II]QMTQSPSTLSASVGDR at m/z 650.933 (Figure 9B). Although 63% of total product ion abundance was assignable to the dominant y series ions, two postulated N-terminal modifications led to the exclusion of this identification. The more probable assignment resulted from a manual inspection, which found that 75% of the total number of peaks (ranging from 2% to 23% of the base peak) corresponded to b series ions, arising from the loss of C3H7NOS from the methionine-alkylated light chain L1 peptide at m/z 650.645. It was also confirmed by MS1 analysis of the ion isotopic m/z values.