# What is the overall charge of the Pro-Met-Phe-Ser-Glu-Leu polypeptide at pH 7.2? I've drawn it, and I think it's -1, but I'm not 100% sure.

I recently got my homework graded and returned, and yep, it's a $- 1$ charge.
The glutamate sidechain has a pKa of $4.07$, making its basic/deprotonated form more dominant at pH $7.2$.
The N-terminus and C-terminus have pKas of ~8.0 and ~3.1, respectively. Therefore, the N-terminus must be acidic/protonated, and the C-terminus must be basic/deprotonated.