Effects of different expression systems on characterization of adenylate deaminase from Aspergillus oryzae

Adenylate deaminase (AMPD) is an amino hydrolase that catalyzes the irreversible hydrolysis of adenosine monophosphate (AMP) to inosine monophosphate (IMP) and ammonia. In this study, the effect of different hosts on the enzymatic properties of AMPD from Aspergillus oryzae GX-08 was investigated and showed that Bacillus subtilis WB600 was more suitable for producing AMPD with a higher activity of 2540 U/mL. After purification, the optimal temperature and pH of recombinant AMPD were 55 °C and pH 6.0, respectively, and its activity was significantly enhanced by 10 mM Fe³⁺ with an increase of 236%. More importantly, the recombinant AMPD specifically and effectively catalyzed the conversion between AMP and IMP, in which 10 mL of crude AMPD achieved a conversion ratio of 76.4% after 40 min. Therefore, B. subtilis WB600 provides a potential platform for producing AMPD with excellent catalytic ability and catalytic specificity.