nucleophile


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nucleophile

[′nü·klē·ə‚fīl]
(physical chemistry)
A species possessing one or more electron-rich sites, such as an unshared pair of electrons, the negative end of a polar bond, or pi electrons. Also known as electron donor.
References in periodicals archive ?
From these calculations, it appears that the nucleophile dependent counter cation has an impact on the transition state energies and course of the ethynyl substitution of F-BODIPY.
The softness of a nucleophile reflects its relative ability to rapidly transfer electron density to the electrophile.
The role of the electrophile is here to form an intermediate complex with the substrate, thereby increasing its reactivity toward the desired nucleophile.
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.
In the splicing reaction, which occurs via two transesterification reactions, the branch site adenosine (A24) 2'-OH acts as a nucleophile and attacks at the 5'-phosphate on the intron site to form a lariat structure.
Generally pH had a greater role than added nucleophile.
The structural results and experimental characterization of the Y6F mutant suggest that the hydrogen bond between Tyr6 and the enzyme-bound nucleophile helps to lower the p[K.
PME-1 is highly conserved from yeast to human and contains a motif found in lipases, which motif has a catalytic triad-activated serine as the active site nucleophile.
of electonic, steric, and orbital effects in the nucleophile.
The proposed mechanism for catalysis of metal ions is from one or combination of the following approaches; (1) coordinating to the substrate and increasing the tendency toward a nucleophilic attack, (2) coordinating to the nucleophile (water) to enhance its reactivity to an electrophilic site, and (3) coordinating to "leaving groups" to facilitate its release from intermediate.
The 3Cpro is distinguished from most other proteases by the fact that it has a cysteine nucleophile but with a chymotrypsin-like serine protease folding.
The assumption of Romsted was that in cases, where nucleophile resides predominantly in Stern layer of the micelle, Menger and Portnoy treatment for unimolecular reaction should hold good for bimolecular reaction also.