alkaline solution + dilute cupric sulfate + protein= ?

[Jon pettersen]

I dont know if this is the right place to mail this question, but I'll 
give it a try and hope someone can help me. 

Alkaline solution  + diluted cupric sulfate, if you add some protein you 
get a violet or pink colour.

What is really happening in this process.

I would be so gratefulif anyone culd give me an answer.

Jon Pettersen.