Identification and characterization of a novel amidase signature family amidase from Parvibaculum lavamentivorans ZJB14001

- A novel amidase signature (AS) amidase (Pl-Ami) was identified by genome mining.
- The recombinant Pl-Ami were purified to homogeneity and characterized in detail.
- The narrow substrate spectrum of Pl-Ami distinguish it from other AS amidases.
- Pl-Ami preferred to hydrolyze long chain aliphatic amides.

Amidase signature (AS) family amidases are known to exhibit broad substrate specificity. According to the available genome sequence data, a novel AS family amidase, Pl-Ami, was identified and cloned from the genome of Parvibaculum lavamentivorans ZJB14001. The recombinant amidase was overexpressed in Escherichia coli BL21, purified and functionally characterized. The optimal pH and temperature for Pl-Ami were 9.5 and 45 °C, respectively. Pl-Ami preferred long chain aliphatic amides as substrates, while no activity was detected towards aromatic, heterocyclic and other amides. The highest enzyme activity of 128 U/mg was obtained when hexanoamide was used as substrate. Kinetic analysis indicated that the extension of chain length of aliphatic amides considerably decreased the Km values, and the turnover number (kcat) was higher with long chain aliphatic amides as substrates. The obtained results provided a distinct understanding of substrate specificity of AS family amidases.