磷酸泛肽基转移酶催化参与初级和次级代谢的载体蛋白的翻译后修饰。聚酮化合物合成酶和非核糖体肽合成酶的功能表达需要通过磷酸氨基肽基转移酶激活所有载体蛋白结构域。在这里，我们通过四种蓝细菌载体蛋白的底物特异性和催化效率来描述五种细菌磷酸泛酰基转移酶的特征。比较的体外磷酸化肽酰化分析显示，Sfp比各种载体蛋白具有最高的催化效率。磷酸泛肽酰转移酶与载体蛋白的体内共表达揭示了磷酸泛肽酰转移酶的广泛底物特异性；所有研究的磷酸泛肽酰转移酶都能够转化载载体蛋白，来自不同的生物合成酶，他们活跃的全息形式。与负责微囊藻毒素生物合成的杂合非核糖体肽合成酶/聚酮合成酶共表达，证实了Sfp的较高体外活性在体内转化为较高的产量。
Phosphopantetheinyl transferases catalyze the post-translational modification of carrier proteins involved in both primary and secondary metabolism. The functional expression of polyketide synthases and nonribosomal peptide synthetases requires the activation of all carrier protein domains by phosphopantetheinyl transferases. Here we describe the characterization of five bacterial phosphopantetheinyl transferases by their substrate specificity and catalytic efficiency of four cyanobacterial carrier proteins. Comparative in vitro phosphopantetheinylation analysis showed Sfp possesses the highest catalytic efficiency over various carrier proteins. In vivo coexpression of phosphopantetheinyl transferases with carrier proteins revealed a broad range substrate specificity of phosphopantetheinyl transferases; all studied phosphopantetheinyl transferases were capable of converting apo- carrier proteins, sourced from diverse biosynthetic enzymes, to their active holo form. Phosphopantetheinyl transferase coexpression with the hybrid nonribosomal peptide synthetases/polyketide synthases responsible for microcystin biosynthesis confirmed that the higher in vitro activity of Sfp translated in vivo to a higher yield of production.
