On the tautomerization process of glycine in aqueous solution

The experimental activation energy for the tautomerization of glycine (zwitterion→neutral form) has been reported to be 14.6 kcal/mol. It has been generally assumed that this energy barrier is needed for proton transfer to occur. However, previous theoretical results do not support this interpretati...

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Bibliographic Details
Published in:Chemical physics letters 2000-05, Vol.321 (5), p.433-437
Main Authors: Tuñón, Iñaki, Silla, Estanislao, Ruiz-López, Manuel F.
Format: Article
Language:English
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Summary:The experimental activation energy for the tautomerization of glycine (zwitterion→neutral form) has been reported to be 14.6 kcal/mol. It has been generally assumed that this energy barrier is needed for proton transfer to occur. However, previous theoretical results do not support this interpretation. In the present work, we examine this question using density functional calculations, extended basis sets and a polarizable continuum solvent model. Our results suggest that the limiting step for the tautomerization process corresponds basically to H-atom reorientation in the –COOH group. This could be a general feature in the tautomerization of amino acids.
ISSN:0009-2614
1873-4448
DOI:10.1016/S0009-2614(00)00365-1