Mechanism of bacterial bioluminescence: 4a,5-dihydroflavin analogs as modelsfor luciferase hydroperoxide intermediates and the effect of substituents at the 8-position of flavin on luciferase kinetics

Thevalidity of the chemically initiated electron exchange luminescence (CIEEL) proposed to explain the bacterial luminescence reaction involving bacterial luciferase was investigated. The study protocol involved the synthesis of various stable 4a,5-dihydroflavin model compounds substituted at the 8-position. The one-electron oxidation potentials of the 4a,5-dihydro forms actas intermediates during catalysis by the flavin-dependent monooxygenase luciferase. The 1-electron oxidation potentials of the model compounds correlated linearly with the corresponding redox potentials, thus supporting the CIEEL.