Isolation, purification and characterization of 5'-phosphodiesterase from Aspergillus fumigatus

5′-Phosphodiesterase (5′-PDE) catalyzes the hydrolysis of ribonucleic acid to obtain a mixture of ribonucleotides, such as 5′-guanosine monophosphate and 5′-adenosine monophosphate. In this study, a 5'-PDE was newly isolated and purified from Aspergillus fumigatus . Following purification, this enzyme exhibited a specific activity of 1036.76 U/mg protein, a molecular weight of 9.5 kDa, and an optimal temperature and pH for enzyme activity of 60°C and 5.0, respectively. However, its activity was partially inhibited by Fe 3+ , Cu 2+ , and Zn 2+ , but slightly improved by the presence of K + and Na + . Additionally, chemical-modification experiments were also applied to investigate the structural information of 5'-PDE, in which the residues containing carboxyl and imidazole groups were essential for enzyme activity based on their localization in the 5′-PDE active site. Furthermore, purified 5′-PDE could specifically catalyze the synthesis of ribonucleotides with a V max 0.71 mmol/mg·min and a K M of 13.60 mg/mL.