17 



Enzyme Kinetics of 

 Hydrolytic Reactions 



I. Introduction 



Modern physics has emphasized the description of the properties of 

 matter and energy in terms of the behavior of elementary particles. In 

 a similar vein, molecular biology describes living systems in terms of 

 their elementary particles, the molecules. This chapter is a discussion 

 of an application of analytical methods to the dynamic behavior (kinetics) 

 of a class of molecules called enzymes. Enzymes are biological catalysts 

 of a primarily protein nature. 1 A catalyst is a chemical substance which 

 alters a rate of reaction, although the catalyst itself is in the same state 

 after the reaction as it was before the reaction. The catalyst may be 

 altered during the reaction but returns to its original state after the 

 completion of the reaction. 



Many uncatalyzed systems exist in nonequilibrium conditions because 

 the reaction rates to reach equilibrium are so slow. A catalyst speeds 

 up the rate of attaining equilibrium but does not in itself alter the 



1 The chemical composition and structure of proteins are discussed in Chapter 15. 



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