[29] Solvent isotope effects on enzyme systems

Publisher Summary This chapter discusses the solvent isotope effects on enzyme systems. The introduction of deuterium in place of protium in the hydrogenic sites of water, and its consequent exchange into some positions of enzymes and substrates produces solvent isotope effects on the kinetic and equilibrium constants associated with the enzymic reaction. These effects, usually expressed as ratios of the appropriate constants in the two isotopic solvents HOH and DOD, are useful in the study of reaction mechanism. The chapter provides (a) the physicochemical background for the use of solvent isotope effects in biochemical studies, with fairly complete derivations of the requisite algebraic expressions, an account of underlying assumptions, and a review of pertinent experimental and theoretical information. (b) to outline workable procedures for carrying out experiments in this area; and (c) to present the apparatus for interpretation of the results.