In this study, we studied the biochemical characterization of flavone synthase I from Daucus carota (DcFNS I) and applied it with flavonoid 6-hydroxylase from Scutellaria baicalensis (SbCYP) to convert flavanones to flavones. The recombinant DcFNS I was expressed in the form of the glutathione-S-transferase fusion protein. Rather than taxifolin, naringenin, pinocembrin, and eriodictyol were accepted as substrates. The optimal temperature and pH for reaction in vitro were 35 °C and 7.5, respectively, and 2-oxoglutarate was essential in the assay system. Co²⁺, Cu²⁺, Mn²⁺, Ni²⁺, and Zn²⁺ were not substitutes for Fe²⁺. EDTA and pyruvic acid inhibited the activity, except for Fe³⁺. Kinetic analysis revealed that the V_max and k_cat values of the recombinant DcFNS I against naringenin were 0.183 nmol mg⁻¹ s⁻¹ and 0.0121 s⁻¹, and 0.175 nmol mg⁻¹ s⁻¹ and 0.0116 s⁻¹ against pinocembrin. However, the recombinant DcFNS I had a higher affinity for naringenin than pinocembrin, with k_M values for each of 0.076 mM and 0.174 mM respectively. Thus, it catalyzed naringenin more efficiently than pinocembrin. Subsequently, using an Escherichia coli and Saccharomyces cerevisiae co-culture system, we successfully converted naringenin and pinocembrin to scutellarein and baicalein respectively. In a synthetic complete medium, the titers of scutellarein and baicalein reached 5.63 mg/L and 0.78 mg/L from 200 mg/L precursors.

在本研究中，我们研究了胡萝卜中黄酮合酶 I (DcFNS I) 的生化特性，并将其与黄芩中的类黄酮 6-羟化酶(SbCYP) 结合，将黄烷酮转化为黄酮。重组 DcFNS I 以谷胱甘肽-S-转移酶融合蛋白的形式表达。而不是紫杉叶素，柚皮素、松果素和圣草酚被接受为底物。体外反应的最佳温度和 pH 值分别为 35 °C 和 7.5，并且 2-酮戊二酸在测定系统中是必不可少的。Co ²⁺、Cu ²⁺、Mn ²⁺、Ni ²⁺和Zn ²⁺不能替代Fe ²⁺. EDTA 和丙酮酸抑制活性，Fe ³⁺除外。动力学分析表明，重组 DcFNS I 对柚皮素的V _max和k _{cat值分别为 0.183 nmol mg} ^-1  s ^-1和 0.0121 s ^-1，以及对 pinocembrin 的 0.175 nmol mg ^-1  s ^-1和 0.0116 s ^-1。然而，重组 DcFNS I 对柚皮素的亲和力高于松树素，k _M值分别为 0.076 mM 和 0.174 mM。因此，它比 pinocembrin 更有效地催化柚皮素。随后，使用大肠杆菌和酿酒酵母共培养系统，我们成功地将柚皮素和松树素分别转化为灯盏花素和黄芩素。在合成完全培养基中，灯盏花素和黄芩素的滴度从 200 mg/L 前体达到 5.63 mg/L 和 0.78 mg/L。