Site-directed mutagenesis of the conserved Ala348 and Gly350 residues at the putative active site of Bacillus kaustophilus leucine aminopeptidase

Detection of leucine aminopeptidase activity in serum using surface-enhanced Raman spectroscopy

A specific reaction-based SERS approach was developed for the selective and sensitive detection of leucine aminopeptidase activity in serum.

Biochemical properties and potential applications of recombinant leucine aminopeptidase from Bacillus kaustophilus CCRC 11223

Experiments were carried out to investigate the effects of various factors on the activity and conformation of recombinant leucine aminopeptidase of Bacillus kaustophilus CCRC 11223 (BkLAP) and potential utilization of BkLAP in the hydrolysis of anchovy protein. Optimal temperature and pH of BkLAP were 70 °C and 8.0 in potassium-phosphate buffer, respectively, and the activity was strongly stimulated by Ni²⁺, followed by Mn²⁺ and Co²⁺. Conformational studies via circular dichroism spectroscopy indicated that various factors could influence the secondary structure of BkLAP to different extents and further induce the changes in enzymatic activity. The secondary structure of BkLAP was slightly modified by Ni²⁺ at the concentration of 1×10⁻⁴ M, however, significant changes on the secondary structures of the enzyme were observed when Hg²⁺ was added to the concentration of 1×10⁻⁴ M. The potential application of BkLAP was evaluated through combination with the commercial or endogenous enzyme to hydrolysis the anchovy protein. Results showed that combining the BkLAP with other enzymes could significantly increase the degree of hydrolysis and amino acid component of hydrolysate. In this regard, BkLAP is a potential enzyme that can be used in the protein hydrolysate industry.