ABSTRACT
This chapter analyses the catalytic mechanism of alcohol dehydrogenase from horse liver at a molecular and electronic level. Based on theoretical and experimental X-ray crystallographic data, it covers aspects of the catalytic mechanism of dehydrogenases in general. Protein flexibility, structural fluctuations around the equilibrium native conformation, and domain movements are considered to be important factors that determine enzyme catalytic properties. Isomerization processes are essential for enzyme catalysis. Two definite subprocesses can be identified independently: one changes the loop 292 to 298 conformation, the other is the catalytic domain rotation about the hinge that closes off the cleft. The main conformational difference between the open and closed structures can be described as a rigid body rotation of each catalytic domain with respect to the central core of the dimer. Information at the molecular level on the rigid body displacement about the hinge has been obtained with molecular mechanics procedure.
