Sepiapterin is a precursor for the synthesis of tetrahydrobiopterin (BH4), which is a wellknown cofactor for aromatic amino acid hydroxylation and nitric oxide synthesis in higher mammals. In this study, a recombinant Escherichia coli BL21(DE3) strain harboring cyanobacterial guanosine 5'-triphosphate cyclohydrolase 1 (GCH1) and human 6- pyruvoyltetrahydropterin synthase (PTPS) genes was constructed to produce sepiapterin. The optimum conditions for T7 promoter-driven expression of GCH1 and PTPS were 30°C and 0.1 mM isopropyl-β-D-thioglucopyranoside (IPTG). The maximum sepiapterin concentration of 88.1 ± 2.4 mg/l was obtained in a batch cultivation of the recombinant E. coli, corresponding to an 18-fold increase in sepiapterin production compared with the control condition (37°C and 1 mM IPTG).
Keywords: 6-pyruvoyltetrahydropterin synthase (PTPS); Escherichia coli; GTP cyclohydrolase 1 (GCH1); Sepiapterin.