Abstract:A gene encoding alkaline phosphatase （AP2）in the genome of Bacillus amyloliquefaciens YP6 was studied via bioinformatics analysis to determine heterologous expression and enzymatic properties.The results showed that the gene was 1 752 bp in length，encoding 583 amino acids.Amino acid sequence analysis showed that AP2 had a molecular mass of 66 kDa with an isoelectric point of 8.62，and it was identified as an alkaline protein with stable structure，high hydrophobicity and signal peptide sequence.Conserved domain analysis and multiple sequence alignment revealed that AP2 could be considered a part of the PhoD superfamily and contained the same or similar metal ion binding sites as other PhoD enzymes.The optimal temperature of AP2 was 30℃ and its optimal pH value was 5.5，which corresponded to a new PhoD enzyme.During the metal ion change，Mn2+，Ba2+and Co2+always activated AP2，whereas Fe2+and Fe3+always inhibited it.Additionally，different concentrations of EDTA-2Na，L-histidine，L-serine and L-cysteine all inhibited AP2 activity.Using DPP and pNPP as substrates for AP2，the values of kcat/Kmwere found to be 1.1×105L/（mmol·s）and 8.8×102L/（mmol·s），respectively.