That depends on what you have. Do you have a FASTA with the whole proteome for all three? Then it should be fairly easy to find a tool or write a script. Just keep in mind that the proteome does not reflect the actual amino acid distribution in the cells at any given time, but only tells you about theoretical proteins.

You may also try the software "Predotar", which is useful for screening the N-terminal of proteomes.

Experimentally this is easy with a total base hydrolysis followed by aa analysis. If you just want the protein composition, then you have to remove the nucleic acids and TCA preciptiate the protein to get rid of the small molecule pool. AA analysis is a standard core lab offering.

Thank you for all recommendations!