▪ Abstract The three-dimensional structures of tryptophan synthase, carbamoyl phosphate
synthetase, glutamine phosphoribosylpyrophosphate amidotransferase, and asparagine
synthetase have revealed the relative locations of multiple active sites within these proteins.
In all of these polyfunctional enzymes, a product formed from the catalytic reaction at one
active site is a substrate for an enzymatic reaction at a distal active site. Reaction
intermediates are translocated from one active site to the next through the participation of an …