What is DPNH2 and what is its function?

Answer 1

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.