[Traumatic Acid]

Hi all.
I have attached an image of my calculations of the net charge of a small poly peptide chain.
The amino acids in question are; Lysine, Tyrosine, and Glutamic acid. I determined the net charge of the polypeptide chain at pH8, to be 0.
If someone can confirm this that would be great. Attached (Hopefully) is an image of my personal calculations.

Thanks in advance. 

[Babcock_Hall]

Your answer may or may not be correct, but your method is suspect.  In a peptide most of the carboxylate groups and amino groups no longer exist in that form, being part of amide bonds (more specifically, peptide bonds).