Figure 2.

SprP is a protease. (A) Escherichia coli DH5α was transformed with plasmid pBBRSP harboring sprP (right) or empty vector (left), plated on agar containing 3% skim milk and plates were incubated for 16 h at 37°C. (B) Cell extracts of strains shown in (A) were prepared after centrifugation and subsequent sonication and tested for proteolytic activity with Suc-Ala-Ala-Pro-Phe-p-nitroanilide as the substrate. Relative activity of 100% corresponds to 0.308; error bars indicate standard deviation.