Where would glycine be neutral?

Glycine, being the simplest amino acid, has specific properties related to its charge that depend on the pH of the environment. At its isoelectric point (the pH at which the amino acid has no net charge), glycine has equal concentrations of positively and negatively charged forms. This means that in a solution at this particular pH, the positive carboxylate (COO-) and the positively charged amino group (NH3+) balance each other out, resulting in a neutral overall charge.

The isoelectric point for glycine is approximately 6.0. At this pH, it exists predominantly in its zwitterionic form, which contains both a positive and a negative charge, but the total charge sums to zero, rendering it neutral. Understanding this concept is essential for predicting the behavior of amino acids in different pH environments and how these properties affect protein structure and function.