(17-19) TRPA1 is also robustly activated by electrophiles
following covalent modification of cysteine (Cys) residues within the ankyrin repeat domain (ARD).
Motohashi, "The Keap1-Nrf2 system as an in vivo sensor for electrophiles
," Nitric Oxide : Biology and Chemistry, vol.
(47) Furthermore, a recent study in cultured liver cancer cells (48) showed that chlorophyllin was one of the most potent inducers of a set of enzymes that protect the cells against potentially harmful oxidants and electrophiles
, two types of unstable molecules that damage tissues and contribute to cancer.
Abbreviations AP-1: Activator protein 1 3-DG: 3-deoxyglucosone 4-HNE: 4-hydroxy-2-nonenal AGEs: Advanced glycation end products ALEs: Advanced lipoxidation end products EpRE/ARE: Electrophile
response element/antioxidant response element GO: Glyoxal Keap1: Kelch-like ECH-associated protein 1 MDA: Malondialdehyde MGO: Methylglyoxal Nrf2: NF-E2-related factor 2 RAGE: Receptor for AGE; RCS, reactive carbonyl species ROS: Reactive oxygen species SAPK/JNK: Stress-activated protein kinase/c-Jun NH(2)-terminal kinase.
A good, more reactive, nucleophile is characterized by a lower value of [mu], [omega] and in opposite a good electrophile
is characterized by a high value of [mu], [omega].
The constant interest of the membrane scientists for PSF is due to its excellent characteristics such as solubility in a large range of polar solvents, chemical stability, thermal resistance (150-170[degrees]C), wide pH value range application (2-12), resistance in oxidative medium (hypochlorite 5-7% and hydrogen peroxide 3-5%), high mechanical resistance of the PSF films (fracture, flexure, and torsion), and moderate reactivity that gives the possibility functionalization by aromatic electrophile
substitution or other reactions (8), (9).
Comparisons of finding with those obtained for an analogous reductive alkylation system revealed the following: (i) lowering the quinone reduction potential greatly enhances the rate of leaving group elimination (e.g., a 2300-fold increase in the rate of chloride elimination accompanies a 200-mV potential decrease), and (ii) lower potentials favor electrophile
trapping (ketonization) over nucleophile trapping of the quinonemethide intermediate .
The possible explanations for these results included metal ions that may activate electrophile
and nucleophile binding, and release electrons to modulate PO activity (Stryer 1995), or divalent cations that may change the secondary structure of certain peptides of PO to influence PO activity (Feng et al.
This important regulatory element was also called the electrophile
responsive element (EpRE) (32).
The remaining 10% is metabolized via the cytochrome P-450 pathway to form N-acetyl-p-benzoquinone imine (NAPQI), a potent electrophile
, which is rapidly converted to a nontoxic moiety and excreted via conjugation with reduced glutathione.
The reaction phenol-formol corresponds to an electrophile
substitution in both acid and alkaline medium where the attack on the para position is supported by polar solvent and the acid conditions whereas the attack on the position ortho is supported by non-polar solvent in the alkaline medium .
Every compound targeted and prepared is new because of the difficulty inherent in traditional and other methods, and the synthesis represents another group of reactions where an anionic nucleophile is condensed with an anionic electrophile
. Also, these and related azole-carboxamides are being prepared and studied for their potential biol.