ABSTRACT
At the molecular level, the basic interaction of a xenobiotic with an enzyme system is characterized by a two-step chemical catalysis (Equation 7.1). The rst step is the reversible formation of xenobiotic-enzyme complex, which is basically a fast, relatively weak hydrogen bonding, ionic or hydrophobic associations, and induce conformational change in the enzyme. The second step is the slower step of irreversible formation of metabolite from enzyme-xenobiotic complex. The basics of kinetics of this catalysis, its relevance to estimation of intrinsic clearance and hepatic clearance are discussed in this chapter.
