YANG Jing,ZHANG Xuejiao,SUN Guanjun,et al.Reaction mechanism of potassium chelated by two α-alanine molecules for scavenging hydroxyl radicals under physiological conditions[J].Acta Scientiarum Naturalium Universitatis Sunyatseni,2025,64(06):53-61.
YANG Jing,ZHANG Xuejiao,SUN Guanjun,et al.Reaction mechanism of potassium chelated by two α-alanine molecules for scavenging hydroxyl radicals under physiological conditions[J].Acta Scientiarum Naturalium Universitatis Sunyatseni,2025,64(06):53-61. DOI: 10.13471/j.cnki.acta.snus.ZR20250093.
Reaction mechanism of potassium chelated by two α-alanine molecules for scavenging hydroxyl radicals under physiological conditions
The reaction mechanism of potassium chelated by two
α
-alanine molecules (
α
-Ala
2
→K
+
) with hydroxyl radicals (OH) under physiological conditions (aqueous phase, 310.15 K, 1.013 × 10
5
Pa) was investigated using the M06-2X and MN15 density functional methods together with the SMD solvation model. Three reaction pathways were identified between
α
-Ala
2
→K
+
and OH: Hydrogen abstraction by OH, OH addition to unsaturated carbon atoms, and single-electron transfer (SET) from
α
-Ala
2
→K
+
to OH. Free energy calculations along the potential energy surfaces revealed that the energy barriers for hydrogen abstraction ranged from 14.0 to 56.1 kJ/mol and were all significantly exothermic. The energy barriers for OH addition ranged from 88.3 to 92.6 kJ/mol, also being exothermic. By contrast, the SET pathway from
α
-Ala
2
→K
+
to OH exhibited a prohibitively high barrier of 795.9 kJ/mol. These results suggest that
α
-Ala
2
→K
+
can effectively scavenge hydroxyl radicals through hydrogen abstraction and addition reactions under physiological conditions.
FISHER G H , D’ANIELLO A , VETERE A , et al , 1991 . Free D-aspartate and D-alanine in normal and Alzheimer brain [J]. Brain Res Bull , 26 ( 6 ): 983 - 985 .
GARRETT B C , TRUHLAR D G , 1979 . Criterion of minimum state density in the transition state theory of bimolecular reactions [J]. J Chem Phys , 70 ( 4 ): 1593 - 1598 .
HRATCHIAN H P , SCHLEGEL H B , 2005 . Using hessian updating to increase the efficiency of a hessian based predictor-corrector reaction path following method [J]. J Chem Theory Comput , 1 ( 1 ): 61 - 69 .
GORB L , LESZCZYNSKI J , 1999 . Intramolecular proton transfer in mono- and dihydrated tautomers of guanine: An ab initio post hartree—Fock study [J]. J Am Chem Soc , 120 ( 20 ): 5024 - 5032 .
MARCUS R A , 1997 . Transfer reactions in chemistry. Theory and experiment [J]. Pure Appl Chem , 69 ( 1 ): 13 - 30 .
MARENICH A V , CRAMER C J , TRUHLAR D G , 2009 . Universal solvation model based on solute electron density and on a continuum model of the solvent defined by the bulk dielectric constant and atomic surface tensions [J]. J Phys Chem B , 113 ( 18 ): 6378 - 6396 .
PÉREZ-GONZÁLEZ A , REBOLLAR-ZEPEDA A M , LEÓN-CARMONA J R , et al , 2017 . Reactivity indexes and O-H bond dissociation energies of a large series of polyphenols: Implications for their free radical scavenging activity [J]. J Mex Chem Soc , 56 ( 3 ): 241 - 249 .
WANG Y , VERMA P , ZHANG L , et al , 2020 . M06-SX screened-exchange density functional for chemistry and solid-state physics [J]. Proc Natl Acad Sci USA , 117 ( 5 ): 2294 - 2301 .
YU H S , HE X , LI S L , et al , 2016 . MN15: A Kohn-Sham global-hybrid exchange-correlation density functional with broad accuracy for multi-reference and single-reference systems and noncovalent interactions [J]. Chem Sci , 7 ( 8 ): 5032 - 5051 .
ZWART L L , MEERMAN J H N , COMMANDEUR J N M , et al , 1999 . Biomarkers of free radical damage Applications in experimental animals and in humans [J]. Free Radic Biol Med , 26 ( 1/2 ): 202 - 226 .