Interaction of Proline with Cu⁺and Cu²⁺Ions in the Gas PhaseGab Yong Lee*Department of Life Chemistry, Catholic University of Daegu, Gyeongsan 712‐702, Korea(Received March 3, 2009)INTRODUCTIONCopper ions are the most important transitionmetals involved in several biological processes ofliving systems, including oxidation, dioxygentransport, and charge transfer.1 The study of interactionsbetween the metal ion and amino acids hasattracted considerable attention from experimental2-6and

Abstract

-proline involves chelation between the two oxygens of the carboxylate group in a zwitterionic proline. The metal ion affinity of proline of the most stable Cu + -proline complex was calculated as 76.0 kcal/mol at 6-311++G(d,p) level, whereas the Cu 2+ ion affinity of proline was calculated as 258.5 kcal/mol.