These primary amine groups become readily available to undergo nucleophilic attack
on oxirane groups of DGEBA, which results in secondary amine groups and increase in the hydroxyl groups (shown in Fig.
First, the oxygen of the glycosidic bond is protonated by the carboxylic acid of an acidic amino acid followed by the formation of the oxazolinium ion intermediate by the nucleophilic attack
of the amide carbonyl group to the anomeric center.
The region for electrophilic attack (red) is localized on the oxygen atoms having double bond with carbon, whereas the nucleophilic attack
is localized on major part of molecule.
energy of activation and entropy of the reaction support bimolecular nucleophilic attack
Nucleophilic elbowThe Ser163 which carries out the nucleophilic attack
on the carbonyl group of TAG is a part of a more conserved structure called nucleophilic elbow.
The nucleophilic attack
by a nitrogen nucleophile, such as hydrazine, hydrazide and hydroxylamine, in carbonyl-containing functionalities, such as an aldehyde or ketone, has been an extensively explored orthogonal approach for protein labeling.
We believe that the mechanism of these reactions consists of the formation of the intermediates A, by nucleophilic attack
of DMSO on the trimethylsilylchloride and B, by nucleophilic attach of oxime on the intermediate A, which undergoes elimination to give the corresponding nitriles (Scheme 2).
The most common reactions involve nucleophilic attack
by GSH on electrophiles, usually epoxides of aromatic and aliphatic organic compounds (Coles and Ketterer 1990).
Beside their ligandin functions, GSTs have another nonconjugating activity, as catalyzing the nucleophilic attack
of GSH on electrophilic oxygen and reduction of cytotoxic hydroperoxides to the less-toxic monohydroxy alcohols.
Attack at positive carbon by alcohol (BD): nucleophilic attack
by hydroxyl group;
These toxins can be neutralized by chemical oxidation, nucleophilic attack
, chemical reduction, and buffering.
to both S and N, which increases the electrophilic character of P and thereby makes degradation via nucleophilic attack