Proline (abbreviated as
Pro or
P; encoded by the codons CCU, CCC, CCA, and CCG) is an
ɑ-amino acid that is used in the
biosynthesis of proteins. It contains an α-amino group (which is in the protonated -+NH3 form under biological conditions), an
α-carboxylic acid group (which is in the
deprotonated –COO- form under biological conditions), and a side chain
pyrrolidine, classifying it as a
nonpolar(at physiological pH),
aliphatic amino acid. It is non-essential in humans, meaning the body can synthesize it from the non-essential amino acid
L-
glutamate.
