Figure 1.

Recombinant bacterial (E. coli) alkaline phosphatases (BAPs) used in this study. (A) Constructs and structural illustration of the recombinant BAPs prepared in this study; BAP-WT, wild-type (unmodified) BAP; BAP-Y, BAP with a peptide tag containing the tyrosine residue (Y-tag) at C-termini; BAP-pG₂pA-Y, BAP with a Y-tagged chimeric antibody-binding protein, pG₂pA-Y, at C-termini; BAP-Loop-Y, BAP-inserted Y-Loop sequence at 221–223 aa. Three of them were tagged with Y-tags that can be recognized by TL. (B) Specific activities of E. coli-expressed BAPs using p-NPP as the substrate. Error bars denote the standard error of the measurements from three individual samples (***p < 0.001).