title: Quantum Chemical Modeling of Enzymatic Reactions: The Case of Decarboxylation.
abstract: We present a systematic study of the decarboxylation step of the enzyme aspartate decarboxylase with the purpose of assessing the quantum chemical cluster approach for modeling this important class of decarboxylase enzymes. Active site models ranging in size from 27 to 220 atoms are designed, and the barrier and reaction energy of this step are evaluated. To model the enzyme surrounding, homogeneous polarizable medium techniques are used with several dielectric constants. The main conclusion is that when the active site model reaches a certain size, the solvation effects from the surroundings saturate. Similar results have previously been obtained from systematic studies of other classes of enzymes, suggesting that they are of a quite general nature.
authors.affiliation: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.|College of Chemistry, Beijing Normal University, Beijing, 100875, People's Republic of China.
authors.forename: Rong-Zhen
authors.initials: RZ
authors.lastname: Liao
authors.affiliation: College of Chemistry, Beijing Normal University, Beijing, 100875, People's Republic of China.
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: Yu
authors.affiliation: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
authors.forename: Fahmi
authors.initials: F
authors.lastname: Himo