Figure 6From: Enhanced synthesis of 5-hydroxy-l-tryptophan through tetrahydropterin regeneration Effect of DMPH 4 concentration on the synthesis of 5-HTP, using the E. coli whole cell reaction. Open circles, l-tryptophan hydroxylation using E. coli tnaA disruptant expressing PAH gene alone; filled circles, l-tryptophan hydroxylation using E. coli tnaA disruptant expressing the genes encoding PAH, PCD, DPR, and GDH.Back to article page