Write the decapeptide with the one letter code

Draw the decapeptide at pH 1,7 and 12 (pay attention to the protonated or deprotonated form of the N- and C-terminal and for each R side group, at the indicated pH)

Calculate the net charge of the peptide for each indicated pH.

Determine the pI of the decapeptide

Ala-Asp-Glu-Tyr-Trp-Pro-Lys-Arg-His-Gly