DIGESTION 441 



Amino Acid Amine Formed 



Arginine Putrescine (tetramethylenediamine) 



Lysine Cadaverine (pentamethylenediamine) 



Phenylalanine Phenylethylamine 



Tyrosine Tyramine (hydroxyphenylethylamine) 



Tryptophan Indolethylamine 



Histidine Histamine (imidazolylethylamine) 



tissues and stimulates gastric acidity. In anaphylactic shock, histamine 

 is fotmd in the blood in dangerously large amounts. The body at- 

 tempts to protect itself against histamine toxicity by means of an 

 enzyme, histaminase, foimd in the intestine. 



The liver is important in detoxication and destroys many toxic 

 compounds. The kidneys inactivate still others. Benzoic acid from 

 intestinal putrefaction is detoxicated by condensing with glycine to 

 form the harmless excretory product, hippuric acid. Likewise, toxic 



CeHs . COOH + +H3N • CH, • GOQ- J^2!!!^ 



benzoic acid glycine 



C6H5 • CO • NH • GH2 • COOH 



hippuric acid 



phenols are excreted as harmless esters of sulfuric acid or glucuronic 

 acid. In other words, the body has a number of protective mecha- 

 nisms for detoxicating harmful products formed in or taken into the 

 body, including reductions, hydrolyses, oxidations, and esterifications. 



REFERENCES 



A Textbook of General Physiology, fifth edition. P. H. Mitchell. McGraw-Hill 



Book Co., New York, 1956. 

 Practical Physiological Chemistry, thirteenth edition. P. B. Hawk, B. L. Oser, and 



W. H. Summerson. Blakiston Co., Philadelphia, 1954. 



