Wiktionary
n. A biogenic amine related structurally to the major neurotransmitter norepinephrine and the biogenic amine octopamine.
Wikipedia
Phenylethanolamine (sometimes abbreviated PEOH), or β-hydroxyphenethylamine, is a trace amine with a structure similar to those of other trace phenethylamines as well as the catecholamine neurotransmitters dopamine, norepinephrine, and epinephrine. As an organic compound, phenylethanolamine is a β-hydroxylated phenethylamine that is also structurally related to a number of synthetic drugs in the substituted phenethylamine class. In common with these compounds, phenylethanolamine has strong cardiovascular activity and, under the name Apophedrin, has been used as a drug to produce topical vasoconstriction.
In appearance, phenylethanolamine is a white solid.
Phenylethanolamine is perhaps best known in the field of bioscience as part of the enzyme name " phenylethanolamine N-methyl transferase", referring to an enzyme which is responsible for the conversion of norepinephrine into epinephrine, as well as other related transformations.