Help: peptide database

[Simone]

Good day,
  I am an Italian biological researcher and I study proteins and
peptides using mass spectrometry. I have I question for you: do you know
if exist, on internet, a peptide database that contain peptide with
aminoacidic mutations?



If yes could you send me the web address?

My E-mail address is:

dtoycr at tin.it

I'm studing the peptide emoglobin mutations and this kind of database
will be very usefull for my work.



Thank you very much for your help