Fig. 3

Calcium ions do not affect HpHtrA activity. a FITC-labeled casein was incubated with 1 µg/ml HpHtrA (times) and 0.008 µg/ml (filled circle), 0.2 µg/ml (filled triangle), and 1.0 µg/ml (filled square) trypsin as a positive control. b FITC-labeled casein was incubated with 1 µg/ml trypsin (filled square), 1 µg/ml trypsin/500 µM CaCl₂ (open square), 1 µg/ml HpHtrA (filled circle), or 1 µg/ml HpHtrA/500 µM CaCl₂ (open circle). Fluorescent signals of the blanks (casein ± CaCl₂) were subtracted from the signals of casein with trypsin or HpHtrA. c Direct comparison of relative fluorescent signals of trypsin- or HpHtrA-treated FITC-labeled casein treated with 500 µM CaCl₂ (+), as indicated, after 15 h. Data from three independent experiments are expressed as relative fluorescent units (RFU) ± SD