The pI of a peptide is determined by examining the ionizable groups when the protonated

and deprotonated forms of each ionizable groups are in equilibrium. Consider the

peptide Lys$-$Glu$-$Trp and answer the following questions:

$1)$ Draw the structure of this peptide when all the ionizable groups are fully protonated.

$2)$ How many ionizable groups does this peptide have? Label the pKa for each of the

ionizable groups in the structure above Draw the appropriate titration curve for this peptide on graph paper starting at pH $0$

and ending at pH $14.$ Label the x$-$axis, y$-$axis and the pKa