This problem refers to the protein buffer in a living system.

"If the blood pH becomes alkaline, there is a release of a proton from the
NH3+ ion, which takes the NH2 form."

I understand that the charge of NH2 must be negative alone and neutral in an amino group. However, the subject of the protein buffer is very briefly touched upon in the text our lecturer gave us and it doesn't detail the reactions in different pH.

I think that since NH3+ loses a positive proton to balance the blood pH during alkaline conditions, this must mean it becomes neutral. The problem is: I'm not sure if NH2 is actually in a group and I suspect that it might be alone, which necessitates that it carry a negative charge.

This is my current understanding of the problem.