Go back  Aspartate Transcarbamoylase:  ATCase - (r2)3(c3)2 Reload
r subunits  -/+ CTP
   (R)/(T) 		c subunit +/- PALA
   (R)/(T) 		  catalytic "230-245 loops"  
(cr2c) + 4 PALA / + 2 CTP 
  (R) /(T)

surface catalytic sites  
c3 + / -  3 PALA 
  (R) /(T)

 c3 + / -  3 PALA 
  (R) /(T)
"Relaxed" (R) Conformation
 catalytic (c) subunits  + PALA ( transition state analog)		 "Tense" (T) Conformation
regulatory (r) subunits + CTP (negative regulatory inhibitor)

@ Duane Sears & Sean R. Christensen
February 03, 2004