To provide for bioluminescence measurements of the enzymatic activities of dehydrogenases, disturbing contaminants were removed from a bacterial luciferase extract by chromatography, using Blue Sepharose CL-6B, a cross-linked agarose to which Cibacrone Blue F3G-A is covalently attached. This compound has a strong affinity to the dinucleotide fold, which is a region in enzymes binding NAD(H) or NADP(H). In contrast to the absorbed dehydrogenases, both luciferase and oxidoreductase were easily eluted and appeared close to the main bulk of UV-absorbing but analytically less important material. A rapid recording of the elution of luciferase was accomplished with a new electrochemical bioluminescence assay. Due to this and the early elution of the desired material, it could be chromatographed, recognized and collected in less than two hours. Thereby the light-yielding capacity of the sensitive material was well preserved. For bioluminescence assay solutions composed of pooled oxidoreductase-luciferase fractions, FMN and a long chain aldehyde were prepared and supplemented with NAD+ and either lactate, malate or 3-hydroxybutyrate. The analyses were carried out in a single step performance by adding the enzyme sample to the luciferase solution. Minute amounts of lactate dehydrogenase, malate dehydrogenase and 3-hydroxybutyrate dehydrogenase yielded a linear light response permitting assay in the lower part of the femtomole region. In case a dehydrogenase does not occur as a contaminant of a commercial luciferase preparation, purification with Cibacrone Blue can be omitted as demonstrated for glucose-6-phosphate dehydrogenase.(ABSTRACT TRUNCATED AT 250 WORDS)