Time dependence of cob(II)alamin concentration following pulsed laser photolysis of adenosylcobalamin at 240 K, and overlaid best-fit biexponential plus constant decay functions (red, smooth curves). Data was collected at times, t < τobs. Fitting parameters are collected in Table 1. (A) Holo-EAL in aerobic solution. (B) Holo-EAL in aerobic solution, with bound (S)-2-amino-1-propanol bound (ternary complex). (C) Holo-EAL in aerobic solution, with bound (S)-1-amino-2-propanol bound (inhibitor complex). (D) Anaerobic solution. Concentrations were as follows: 60 μM EAL, 30 μM AdoCbl, 5 mM (S)-2-amino-propanol, 5 mM (S)-1-amino-2-propanol.