Chapter 3, Problem 36P

Glycine is an amino acid that can be obtained from most proteins. In solution, glycine exists in equilibrium between two forms:

${\text{H}}_{\text{2}}{\text{NCH}}_{\text{2}}{\text{CO}}_{\text{2}}\text{H}\rightleftharpoons {\text{H}}_3\stackrel{+}{\text{N}}{\text{CH}}_{\text{2}}{\text{CO}}_2^{-}$

(a) Consult Table 3.1 and state which form is favored at equilibrium.

(b) A handbook gives the melting point of glycine as $262°\text{C}$ (with decomposition). Which of the structures given above best represents glycine?