Evidence for the presence of an unknown factor, active in the light reaction, in preparations of Photobacterium phosphoreum

Abstract

An enzyme-free fraction, obtained from Photobacterium phosphorem, increases the light reaction caused by addition of FMNH to diluted enzyme lysates containing palmital. Evidence was obtained that this fraction contains a factor which dissociates from a complex with luciferase. Apart from its activating action the factor, probably, protects luciferase against inactivation. The factor is thermolabile.

Active luciferase preparations as well as solutions containing the activating factor contain a substance fluorescing in the 470-mμ region. No arguments are found, as yet, for the luciferase activating factor to be identical with this fluorescing substance.

The number of DPNH molecules utilized per light quantum emitted in our preparations was measured to be about 150.