noun. a non-vital amino acid found in most proteins. It is a precursor of the catecholamine neuro-transmitters: norepinephrine, dopamine, and epinephrine, that vary anatomically only in the group at one position of the molecule.
noun. a non-vital amino acid found in most proteins. It is a precursor of the catecholamine neuro-transmitters: norepinephrine, dopamine, and epinephrine, that vary anatomically only in the group at one position of the molecule.