Figure 3.

2′,3′-cAMP is formed upon incubation of ApA with Fe²⁺ or Mg²⁺. HPLC chromatograms show the accumulation of 2′,3′-cAMP, a direct product of in-line cleavage, upon incubation of ApA with either (A) 25 mM Fe²⁺, (B) 25 mM Mg²⁺ or (C) no metal as the negative control. Panel (D) shows identification of the 2′,3′-cyclic adenosine monophosphate by LC–MS of ApA incubated with 25 mM Fe²⁺ for 2 days. Labeled species correspond to [M−H]⁻ ions. Reactions were incubated anoxically at 37°C in the presence of 5% (v/v) glycerol.