Synthetic applications of tryptophan synthase

Tryptophan synthase catalyzes the final two steps in L-tryptophan synthesis in bacteria and plants. The alpha-subunit catalyzes the reversible retroaldol cleavage of indole-3-glycerol phosphate to give indole and D-glyceraldehyde-3-phosphate, and the beta-subunit catalyzes the condensation of indole with L-serine to give L-tryptophan. The alpha-reaction has been used for the synthesis of indole-3-glycerol phosphate, but has not been investigated extensively for synthesis of analogues. The beta-reaction has been used for the preparation of a wide range of analogues of L-tryptophan, including chloro and azido benzene ring-substituted tryptophans, as well as aza, thia, and selena heterocyclic analogues. In addition, S-alkyl and S-aryl cysteines, Se-alkyl selenocysteines, as well as beta-nitrogen substituted alanines have been prepared. (C) 2004 Elsevier Ltd. All rights reserved.