Numerous earlier studies on various light-producing species have
suggested a
relation between luminescence and fiavin compounds,1-8 although
it has not been
demonstrated heretofore that the enzymatic oxidation of reduced
flavins by
luminous bacterial extracts will result in luminescence. From
the similar kinetics
of light emission when either flavin mononucleotide (FMN=
riboflavin phosphate)
or reduced diphosphopyridin nucleotide (DPNH2=reduced coenzyme
I) was the
last factor added to luminous bacterial extracts,9 it seemed
probable that the sole
function of DPNH2 in luminescence was to produce reduced flavin,
and, further,
that reduced flavin might be considered as bacterial luciferin.
Because of technical
difficulties in handling reduced flavins these compounds were
not used in earlier
studies on the extracted cell-free luminescent system from
bacteria. We can now
report that either reduced riboflavin or reduced flavin
mononucleotide will support
the luminescence of Achromobacter fischeri extracts in the
absence of added DPNH2.
