Lysine is a precursor for desferrioxamine siderophore biosynthesis. The pathway is often initiated by lysine decarboxylases. However, little is known about those enzymes from Actinobacteria which represents a diverse class of desferrioxamine producers. In this study we focused on the genes grdesA form Gordonia rubripertincta CWB2 and psdesA from Pimelobacter simplex VkMAC-2033D that encode decarboxylases presumed to be involved in the synthesis of desferrioxamine siderophores. The corresponding proteins GrDesA and PsDesA, were heterologously produced in Escherichia coli and purified. PsDesA was isolated bound to the cofactor pyridoxal 5-phosphate and GrDesA was purified in its apo form. PsDesA showed a moderate substrate preference for lysine (K_m = 0.17 mM, k_cat = 0.26 s⁻¹) compared to ornithine (K_m = 0.13 mM, k_cat = 0.14 s⁻¹), while GrDesA exhibited specificity for lysine (K_m = 0.13 mM, k_cat = 1.2 s⁻¹) compared to ornithine (K_m = 2.9 mM, k_cat = 0.18 s⁻¹). The maximum decarboxylase activity of PsDesA was achieved at pH 7.5 at 35 °C, although PsDesA was stable up to 40°, its relative activity decreased significantly at 50 °C. The temperature optimum (40 °C) and thermostability of GrDesA were likewise, but it exhibited maximum activity at pH range 8.0–8.5, and sharply decreased outside of this range. The expression and characterization of these two decarboxylases provides insight into the biosynthetic pathway of desferrioxamines from G. rubripertincta and P. simplex and supports the functional annotation of related pathways.

赖氨酸是去铁氧铁铁载体生物合成的前体。该途径通常由赖氨酸脱羧酶引发。然而，对于来自放线菌属的那些酶的了解很少，所述放线菌属代表各种类型的去铁草胺生产者。在这项研究中，我们侧重于基因格迪萨形成大头rubripertincta CWB2和psdesA从Pimelobacter单纯VkMAC-2033D是编码脱羧酶假定参与铁载体去铁胺的合成。在大肠杆菌中异源产生并纯化相应的蛋白质Gr DesA和Ps DesA 。聚苯乙烯分离出与辅因子5-磷酸吡al醛结合的DesA，并以脱辅基形式纯化Gr DesA。与鸟氨酸（K _m  = 0.13 mM，k _cat  = 0.14 s ^-1）相比，Ps DesA对赖氨酸（K _m  = 0.17 mM，k _cat  = 0.26 s ^-1）显示适中的底物偏好，而Gr DesA对赖氨酸具有特异性（K _m  = 0.13 mM，k _cat  = 1.2 s ^-1）与鸟氨酸（K _m  = 2.9 mM，k _cat  = 0.18 s ^-1）。在35°C的pH 7.5下，Ps DesA的最大脱羧酶活性得以实现，尽管Ps DesA在高达40°的温度下仍保持稳定，但其相对活性在50°C时却明显降低。Gr DesA的最适温度（40°C）和热稳定性也相同，但在pH范围8.0–8.5中表现出最大活性，在此范围外急剧降低。这两种脱羧酶的表达和表征提供了对来自G. rubripertincta和P. simplex的去铁草胺的生物合成途径的深入了解，并支持了相关途径的功能注释。