THE NATURE OF ENZYME ACTIVE CENTERS 



201 



R^ ^ PAPAIN 



" C-NH 



+ o 

 o^- o 



K C-NH, 



^ o " o 6 



■■■V' SH 



„. t 



K -. c= 



0,-^0 I +NH3 



OH 



0-0 



■I- R-coo 



SARCOSINE OXIDASE 



^ 



\v 



,/~H~H PT^ 



(-C-C-H H-C-h1\ ■• c— o 



s\_HjH^___i_y v\ /■••• 



CARBOyVPEPTIDASE 



rUMARASE 



Fig. 6-2. (continued) 



electron-transport system. The FAD is bound to the protein electrostatically through 

 the phosphate groups at Rj and to electrophilic groups through the ring at Rj and 

 R3, while interaction with a non heme iron occurs by which the electrons are transferred 

 to cytochrome c, the iron ion being bound to the protein at R4 and Rj. (Mahler and 

 Elowe, 1954.) 



Acetylcholinesterase: The substrate is bound electrostatically to the anionic site 

 (probably a carboxylate group) and the ester link is subjected to the esteratic site 



