Activities of PPa1, PPa54, with comparisons between each phage-encoded protein and its corresponsive controls. P1: the commercial pyrophosphatase (PPa, 1000 U mL -1 ) of Escherichia coli was used as a positive control for both PPa1 and PPa54. N: the total protein from the recombinant E.coli cells transformed with an empty pET28a vector was used as a negative control.
