212 



6. INTERACTIONS OF INHIBITORS WITH ENZYMES 



between them is much greater than the lengths of the dipoles, the potential 

 energy is given by (Moelwyn-Hughes. 1957, p. 301): 





(2 cos « cos 



sin a sin ji) 



(6-15) 



The potential energies for certain configurations are shown in Fig. 6-4 (b), 

 from which it is seen that the maximal attraction occurs when the dipoles 

 are oriented in a head-to-tail position. 



Interactions of substrates and inhibitors with enzymes must often occur 

 at distances which are not markedly greater than the dipolar lengths. It 

 is thus necessary to enquire into the energies involved at these shorter 

 distances. The two configurations shown in Fig. 6-5 lead to the following 

 expressions for the potential energy: 



Parallel: 



Va 





1 



Vl' + d' 



(6-16) 



Fig. 6-5. Interactions of two dipoles at small distances. 



