| 摘要 |
The present invention provides novel methods for producing doxorubicin using daunomycin as a substrate. One method employs a genetically engineered host microorganism which is transformed with a vector, preferably a plasmid, which contains the doxA gene. Preferably, the doxA gene, also referred to herein as "doxA", is cloned into a plasmid which is then introduced into the host microorganism, preferably a bacterial host, more preferably Streptomyces, to provide a transformed host microorganism. The doxA gene, when present on a plasmid, confers on the transformed host the ability to convert daunomycin and 13-dihydrodaunomycin, to doxorubicin. The doxA gene encodes a P450-like enzyme which catalyzes the hydroxylation of daunomycin and 13-dihydrodaunomycin at C-14 to form doxorubicin; such enzyme is designated "daunomycin C-14 hydroxylase". Thus, the expression of doxA in the transformed host using a plasmid which contains doxA enables the transformed host to convert daunomycin to doxorubicin. The doxorubicin is then extracted from host microorganism cultures.
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