Journal Article Research Support, Non-U.S. Gov't EC 3.4.24.24 Matrix Metalloproteinase 2 QM/MM matrix metalloproteinases proteolysis reaction Alcohols IQA Oligopeptides QTAIM density functional theory descriptors of chemical bonding electron density exchange correlation free energy hydrogen bond one-electron potentials potential acting on an electron in a molecule quantum chemistry quantum mechanics/molecular mechanics source function