| 摘要 |
PROBLEM TO BE SOLVED: To provide a microorganism that is a mutant bacterial strain of the species Actinosynnema pretiosum, being capable of producing maytansinoid ansamitocins such as ansamitocin P-3 in improved yield, related to maytansinoids that have potent cytotoxic activity and demonstrate strong anti-tumor activity when delivered in conjugate form with a cell-binding agent, and to provide methods for producing such maytansinoid ansamitocins.SOLUTION: There are provided a microorganism that is a mutant bacterial strain of the species Actinosynnema pretiosum, designated PF4-4, being capable of producing maytansinoid ansamitocins such as ansamitocin P-3 in improved yield compared to previous known strains, and capable of growing under varied culture conditions, and methods for producing maytansinoid ansamitocins by culturing PF4-4 in a suitable growth medium. |
