proteinogenic amines, a group of nitrogen-containing organic compounds that form in human, animal, plant, and bacterial organisms through the decarboxylation (splitting off of the COOH group) of amino acids. Many biogenic amines—histamine, serotonin, noradrenaline, adrenaline, tyramine, and others—are biologically active substances that affect processes of inhibition and excitation in the cerebral cortex and the subcortical centers and evoke changes in blood pressure—by means of vasodilation or vasoconstriction—and other bodily changes. Many biogenic amines that are formed in the large intestine in man and animals by the action of putrefactive bacteria are toxic. Biogenic amines are biologically inactivated primarily by means of oxidative deamination (splitting off of the amino group), which is catalyzed by a group of enzymes—the amine oxidases. Adenosine phosphoric acids, nucleic acids, and high-molecular-weight carbohydrates such as heparin play an important role in the binding of biogenic amines by biochemical cell components. Biogenic amines present in cells in a bound state are inactive and are not affected by amine oxidases.