I've noticed that some textbooks and video lectures use an amino acid wherein the amino group has two hydrogens, and others use an amino acid with three hydrogens in the amino group (in the formation of a peptide bond).
How come there are two variations? And also, if the starting amino acid has three hydrogens in its amino group, what is the mechanism for the part that the nitrogen bonded to the carbonyl ends up having one hydrogen attached to it?
I worked up the mechanism on the former condition, but starting with three hydrogens, I don't quite get it. I hope you someone can enlighten me.