• 1. The emission spectrum of in vitro firefly bioluminescence has been found to be identical with the in vivo bioluminescence.
  • 2. One light quantum is emitted for every luciferin molecule oxidized, the yellowgreen emission band peaking at 562 mμ.
  • 3. A low quantum yield red emission appears in acid pH and at high phosphate buffer concentrations even at neutral pH.
  • 4. An energy stabilization role is postulated for the luciferase molecule in view of the high quantum yields measured.
  • 562 um peak in radiation