Quantum yields and kinetics of the firefly bioluminescence reaction of beetle luciferases

Quantum yields of firefly bioluminescence reactions were determined for beetle luciferases from the three main families of luminous beetles emitting different bioluminescence colors. Quantum yield (QY) was significantly correlated with luminescence spectrum. The green light-emitting luciferase of the Brazilian click beetle, Pyrearinus termitilluminans, whose luminescence spectrum had the shortest peak wavelength of all the luciferases investigated, had the highest QY (0.61). Mutant analyses of active site-substituted Pyrocoelia miyako luciferases showed that, although k(cat) was decreased by the mutations, the QY was not significantly affected.