Structure of Bleomycin and Analogues

As stated, the antibiotics are isolated as their blue copper(II) chelates. The copper can be easily removed as sulfide with H2S and the blue color regenerated by addition of excess copper(II). The metal is believed to be 

In bioinorganic terms, the chemistry of bleomycin can be divided into that of its metal complexes, their reaction with and activation of oxygen, and the interaction and inactivation of DNA. 

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