Quantum mechanical methods for enzyme kinetics

Methods for incorporation of quantum mechanical effects into enzyme kinetics simulations in which the enzyme is an explicit part of the model are discussed with emphasis on three aspects. The first is the use of quantum mechanical electronic structure methods such as molecular orbital theory and density functional theory, usually in conjunction with molecular mechanics. The second is treating vibrational motions quantum mechanically in an instantaneous harmonic approximation, or by path integrals, or by a three-dimensional wave function coupled to classical nuclear motion. The third is incorporation of multidimensional tunneling approximations into reaction rate calculations.