1. Mechanism of allergic contact dermatitis from propacetamol: sensitization to activated N,N-diethylglycine
V Berl, A Barbaud, J P Lepoittevin Contact Dermatitis. 1998 Apr;38(4):185-8. doi: 10.1111/j.1600-0536.1998.tb05704.x.
In order to confirm the mechanism of skin sensitization to propacetamol, a pro-drug of acetaminophen, 3 patients with allergic contact dermatitis from propacetamol were patch tested with N,N-diethylglycine phenyl ester, an activated form of N,N-diethylglycine. Positive patch tests were observed in all the patients at 10% in pet., while 20 control patients remained negative. This strongly suggests that propacetamol is acting as an activated form of N,N-diethylglycine, transferring this part of the molecule to nucleophilic residues of proteins. This also explains why reactions to acetaminophen have never been observed in patients sensitized to propacetamol.
2. Extended Diethylglycine Homopeptides Formed by Desulfurization of Their Tetrahydrothiopyran Analogues
Marta De Zotti, Jonathan Clayden Org Lett. 2019 Apr 5;21(7):2209-2212. doi: 10.1021/acs.orglett.9b00501. Epub 2019 Mar 12.
Diethylglycine (Deg) homopeptides adopt the rare 2.05-helical conformation, the longest three-dimensional structure that a peptide of a given sequence can adopt. Despite this unique conformational feature, Deg is rarely used in peptide design because of its poor reactivity. In this paper, we show that reductive desulfurization of oligomers formed from more reactive tetrahydrothiopyran-containing precursors provides a practical way to build the longest Deg homopeptides so far made, and we detail some conformational studies of the Deg oligomers and their heterocyclic precursors.
3. Modulation of Glycinergic Neurotransmission may Contribute to the Analgesic Effects of Propacetamol
Lukas Barsch, Robert Werdehausen, Andreas Leffler, Volker Eulenburg Biomolecules. 2021 Mar 25;11(4):493. doi: 10.3390/biom11040493.
Treating neuropathic pain remains challenging, and therefore new pharmacological strategies are urgently required. Here, the enhancement of glycinergic neurotransmission by either facilitating glycine receptors (GlyR) or inhibiting glycine transporter (GlyT) function to increase extracellular glycine concentration appears promising. Propacetamol is a N,N-diethylester of acetaminophen, a non-opioid analgesic used to treat mild pain conditions. In vivo, it is hydrolysed into N,N-diethylglycine (DEG) and acetaminophen. DEG has structural similarities to known alternative GlyT1 substrates. In this study, we analyzed possible effects of propacetamol, or its metabolite N,N-diethylglycine (DEG), on GlyRs or GlyTs function by using a two-electrode voltage clamp approach in Xenopus laevis oocytes. Our data demonstrate that, although propacetamol or acetaminophen had no effect on the function of the analysed glycine-responsive proteins, the propacetamol metabolite DEG acted as a low-affine substrate for both GlyT1 (EC50 > 7.6 mM) and GlyT2 (EC50 > 5.2 mM). It also acted as a mild positive allosteric modulator of GlyRα1 function at intermediate concentrations. Taken together, our data show that DEG influences both glycine transporter and receptor function, and therefore could facilitate glycinergic neurotransmission in a multimodal manner.
