Kedarcidin and neocarzinostatin belong to the chromoprotein family of endiyene antibiotics and have potent antitumor activity. Their structures consist of an apoprotein and a nonpeptide chromophore. Apoprotein has been known to be essential to stabilize and regulate the availability of a labile chromophore. Here, we have identified the complete kedarcidin apoprotein gene (kedA) from Streptoalloteichus sp. ATCC 53650 (Actinomycete L585-6). KedA was characterized by a comparative study with neocarzinostatin apoprotein (NcsA). Overexpression of kedA resulted in a ~ 2-fold enhanced production of kedarcidin in Streptoalloteichus sp., whereas overexpression of ncsA resulted in a ~ 1.6-fold enhanced production of neocarzinostatin in Streptomyces carzinostaticus ATCC 15944. Moreover, the apoprotein-overexpressed strain showed a high growth rate, which demonstrates that the apoprotein not only protects the labile chromophore, but also tolerates the toxicity of endiyene antibiotics in the host strain.