Important Role of the 3-Mercaptopropionamide Moiety in Glutathione: Promoting Effect on Decomposition of the Adduct of Glutathione with the Oxoammonium Ion of TEMPO
摘要:
Cyclic voltammetry of TEMPO in aqueous 0.1 M NaOH in the presence of glutathione (GSH) or cysteine (Cys) indicated the following points: (i) Both of the thiols rapidly formed adducts 3 with oxoammonium ion 1 anodically generated from TEMPO. (ii) 3 generated from GSH entered a succeeding reaction that generated N-oxide anion 2(-) (the reduced TEMPO). (iii) 3 produced from Cys remained intact over the time scale of voltammetry. A structural feature of GSH was considered to contribute to the observed behavior of this tripeptide. Possible structural features were evaluated by screening various thiols on the basis of whether they provided GSH-like voltammetric results. The 3-mercaptopropionamide group with an amide hydrogen in GSH was determined to be responsible for the observed difference between GSH and Cys. The likely function is to transform 3 from GSH into a 5-imino-1,2-oxathiolane intermediate, thereby releasing 2(-). Product analysis for reactions of model thiols representing GSH and Cys with 1 provided support for this argument and suggested that the reaction of GSH or Cys with 1 would produce the corresponding disulfides, regardless of whether a five-membered ring intermediate was formed. The proposed function of the 3-mercaptopropionamide moiety of GSH may provide useful insight for the molecular design of exogenous thiol compounds as novel drugs for the treatment of GSH-depletion-related disorders.
Ketamine esters and amides as short-acting anaesthetics: Structure-activity relationships for the side-chain
作者:Ivaylo V. Dimitrov、Martyn G. Harvey、Logan J. Voss、James W. Sleigh、Michael J. Bickerdike、William A. Denny
DOI:10.1016/j.bmc.2019.02.010
日期:2019.4
N-Aliphatic ester analogues of the non-opioid ketamine (1) retain effective anaesthetic/analgesic properties while minimising ketamine's psychomimetic side-effects. We show that the anaesthetic/analgesic properties of these ester analogues depend critically on the length (from 2 to 4 carbons), polarity and steric cross-section of the aliphatic linker chain. More stable amide and ethylsulfone analogues generally
1-Phenylpyrazolo[3,4-d]pyrimidines as adenosine antagonists: the effects of substituents at C4 and C6
作者:Mary Chebib、Ronald J. Quinn
DOI:10.1016/s0968-0896(96)00240-4
日期:1997.2
Forty-two 1-phenyl-pyrazolo[3,4-d]pyrimidines substituted at C6 with thioethers containing distal amide substituents and substituted at C4 with thiol, thiomethyl or amino were synthesized and tested for adenosine A(1) and A(2a) receptor binding. Compared with a thiol at C4, both S-methylation and conversion to an amino resulted in increased affinity at both receptors with the C4 amino compounds having the highest affinity. The C-4 region of the receptor consists of an alkyl pocket containing a hydrogen-bonding site. The study established that for high affinity at both the A(1) and A(2a) adenosine receptors the distal amide should be separated from the C6 thiol by only one carbon. In this study, 2'-(4-amino-1-phenylpyrazolo[3,4-d]pyrimidin-6-ylthio)- N-ethyl-ethanamide (4b) had the highest affinity at the A(1) receptor with a K-i of 12.1 nM while 2'-(4-amino-1-phenylpyrazolo[3,4-d]pyrimidin-6-ylthio)ethanamide (4a) had the highest affinity at the A(2a) receptor with a K-i of 44.9 nM. (C) 1997, Elsevier Science Ltd.
Targeting new N-furfurylated 4-chlorophenyl-1,2,4-triazolepropionamide hybrids as potential 15-lipoxygenase inhibitors supported with <i>in vitro</i> and <i>in silico</i> studies
Investigations of <i>p</i>-tolyloxy-1,3,4-oxadiazole propionamides as soybean 15-lipoxygenase inhibitors in comforting with <i>in vitro</i> and <i>in silico</i> studies