ISSN:
0947-6539
Keywords:
amino acids
;
biosynthesis
;
hydroxylations
;
nitric oxides
;
semiempirical calculations
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The electronic structure (charge distribution, bond indices, character of the frontier orbitals) and geometry (bond distances and angles) of L-arginine and N-methyl-L-arginine were determined by means of the INDO procedure. The method was also adopted to model the conversion of L-arginine into N-hydroxy-L-arginine in biological systems. This revealed that the approach of diatomic O species does not result in reaction, whereas the approach of either an O atom or an O2- ion leads to insertion of oxygen and formation of hydroxy-L-arginine. The insertion of oxygen between the nitrogen and hydrogen atoms leads to more stable products than insertion into the C-H bond. The same results were obtained for N-methyl-L-arginine, and are consistent with the hypothesis that the inhibitive effect of N-substitution in L-arginine is of no importance for the first step in the biosynthesis of NO (hydroxylation process). The mechanistic considerations based on the charge distribution and frontier orbital characteristics led to the conclusion that the most probable mechanism of L-arginine hydroxylation consists in electrophilic attack of [FeO]3+ at the Nω-H bond, initiated by the reduction of L-arginine+, followed by insertion of oxygen and product oxidation.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/chem.19970030417
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