Time resolved fluorescence of AHis:BThr:(DPP)Zn in 50 mM Pi, 150 mM NaCl, pH 7.5 buffer, λex = 405 nm. (A) Fluorescence spectra obtained at various time delays (black, <1 ns; red, 1 ns; blue, 2 ns; green, 3ns; orange, 4 ns; yellow, 10 ns. (B) The kinetic profile obtained from the time-dependent integrated emission over the 600 – 700 nm spectral region; the red line is a first-order fit yielding a time constant of 4 × 108 s−1.