(redirected from ptomain)
Also found in: Dictionary, Thesaurus, Medical, Idioms, Wikipedia.


, ptomain
any of a group of amines, such as cadaverine or putrescine, formed by decaying organic matter



any of various nitrogenous chemical compounds formed during the putrefactive decomposition of proteins, processes aided by microorganisms, in such substances as meat, fish, and yeast. Prime examples of ptomaines are biogenic amines, including putrescine and cadaverine, and methylguanidine, agmatine (aminobutyl guanidine), and neurine (trimethylvinyl-ammonium hydroxide). Histamine, tyramine, and tryptamine, which are obtained upon enzymatic decarboxylation of the corresponding amino acids, are also examples of ptomaines.

The idea that ptomaines are responsible for ptomaine poisoning is erroneous, since most ptomaines exhibit a low degree of toxicity. The sole exception to this is neurine, whose effect on the human body resembles that of muscarine—the poison of the mushroom fly agaric (Amanita muscaria). The toxicity of the products of protein decay derives from the presence of strong bacterial toxins. Nearly all ptomaines are normal products of human and animal metabolism; some ptomaines exist in the free state in fungi, brewers’ yeast, higher plants, and food products (cheese). Since the amines that constitute ptomaines have various chemical natures, biological functions, and physiological effects, the term “ptomaine” has become archaic and is rarely used.