Figure 2.

ζ toxin phosphorylates in vitro a fraction of UNAG. Samples containing 2 mM UNAG and 0.5 mM ATP were incubated in the absence (A) or presence (B) of ζ toxin (0.5 µM) for 60 min at 30 °C in buffer B. The reaction products were analyzed by mass spectroscopy. The peaks corresponding to relevant products (ATP, ADP, UNAG and UNAG-3P) are indicated. The intensity (×10⁴) was expressed in arbitrary units (a.u.). In panel B, the 675 to 740 m/z section is enlarged in the insert.