Question

Why do amino acids have high melting point ?

Answer 1

Both acidic (carboxyl) as well as basic(amino) groups are present in the same molecule of amino acids. In aqueous solutions carboxyl group can lose protons and the amino group can accept a proton thus giving rise to a dipolar known as zwitter ion. Due to this dipolar behavior they have strong electrostatic interactions within them. For this reason melting point of amino acids is high.