Active Insulin analysis

[adinboy]

So I have a question about the active form of insulin. I know the 1 letter amino acid sequence for insulin is:

 

GIVEQCCTSICSLYQLENYCNFVNQHLCGSHLVEALYLVCGERGFFYTPKT

 

I used http://web.expasy.org/compute_pi/ to calculate the theoretical pI of insulin which is around 5.39. The question is what the charge of this insulin would be in a pH solution of 7.4.

 

The exact question is: At pH 7.4, what would be the charge (if any) for insulin? Explain how you came to that conclusion.

 

I know when in a pH solution that is higher than the pI value of the protein then the amino acid will be deprotinated and migrate to the positive side. So would the answer be that it is negatively charge or do I have to come up with an exact number like -2?