Figure 4. Comparison of detection sensitivity between Prussian blue agar assay (A) and Fe^IIIXO agar assay (B).

LAAO produced by Pseudoalteromonas sp. R3 (R3-LAAO) was used to oxidize the different L-amino acids including L-Cys, L-Glu, L-Asp, L-Val, L-Ala, L-Ser, L-Gly and L-Pro, in separate reactions, and subsequently the produced H₂O₂ in oxidization solution was measured with both Prussian blue agar assay [17] and Fe^IIIXO agar assay. For the Prussian blue agar assay, the standard H₂O₂ with concentration of 10 mM was used as the positive control (PC1); in contrast, for the Fe^IIIXO agar assay, the standard H₂O₂ with concentration of 50 µM was treated as the positive control (PC2). For both assays, the reaction solution without L-amino acid was used as the negative control (NC).