Below are few examples of DNA cleavage shown by natural enediynes (Scheme 6-11).

Scheme 6. Mechanism of DNA cleavage by Calicheamicin

| Scheme 7. Mechanism of DNA cleavage by Calicheamicin |

| Scheme 8. Mechanism of biological action of dynemicin A. |

| Scheme 9. Mechanism of DNA cleavage by Neocarzinostatin (zinostatin). |

Scheme 10. Proposed mechanism of action of the kedarcidin chromophore. |

Scheme 11. Mechanism of biological action of dynemicin A. |