POISONOUS AMINES 589 



of alkaptonurics who cannot destroy lioniogentisic acid. That is, 

 their deficiency involves only one of two possible methods of oxidizing 

 aromatic compounds, leaving them considerable capacity for this im- 

 portant metabolic function. The tissues of the alka[)tonuric are prob- 

 ably not chemically affected in this condition, for Abderhalden" found 

 that the hair and nails of an alkaptonuric contained normal propor- 

 tions of tyrosine. There is often an arthritis, from deposition of pig- 

 ment in the joints, designated ))y Gross^^ as "arthritis alkaptonurica." 

 In some cases of alkaptonuria a pigmentation of the cartilages also 

 occurs, ochronosis, but the association is not constant; ochronosis may 

 occur without alkaptonuria, and conversely. (See "Ochronosis.") 



(2) Substances Arising from the Fatty Acid Radicals (Amino Acids) 



OF Proteins 



As stated in the introductory chapter, the protein molecule consists of a com- 

 bination of a great number of organic acids, of various sorts, all of which have as a 

 common characteristic the presence of a NH-. group attached to the carbon atom 

 nearest the acid radical, the a position; thus, R — CHXHo — COOH. A few of 

 the amino acids contain an aromatic group, and the relation of these to intestinal 

 decomposition has been considered above. The greater number have a simple 

 fatty acid radical (the simplest amino-acid being glycine, CHoXHj — COOH), and 

 from them are derived by intestinal putrefaction substances that are, for the most 

 part, chemically simple and, as far as known, pathologically unimportant. From 

 leucine alone is derived a substance of known coasiderable toxicitv, the pressor 

 CH. 



base isoatnylamine. ^ CH— CH2 — CH2 — XH-j which is less powerful than 



CH3 

 the cyclic pressor bases described previously. Bain'^" found it the most abundant 

 pressor base of the urine. 



Fatty acids may readily be formed from them by splitting out of the NHj 

 group; thus acetic acid may be formed from glycine, propionic acid from alanine, 

 etc. Apparently butyric and acetic acid are the acids most commonly formed in 

 this way. Gaseous derivatives, such as hydrogen, ammonia, carbon dioxide, and 

 marsh-gas, are also produced. Acetone is perhaps formed from these fatty acids; 

 it is often present in the intestinal contents, but may come from other sources. 



Certain conditions of cyanosis have been designated as enterogenous cyanosis, 

 (See Methemoglobin, Chap, xviii) because of the belief that the methemoglobin 

 responsible for the cyanosis is caused by nitrites derived from intestinal putrefac- 

 tion and demonstrable in the blood.*" Presumably the nitrites come from the 

 XHo groups of the protein molecule, the colon bacillus being an active former of 

 nitrites. Under the same term are included the cases of snlph-hemoglobinemia. 

 This condition is ascribed by Wallis*' to bacteria which produce from the proteins 

 a hydroxylamine derivative, capable of reducing oxyhemoglobin, and which he 

 finds present in the blood of patients with sulph-hemoglobinemia. 



Diamines. — Of much interest are the substances that are formed from the 

 amino-acids by bacterial action, which still retain. their nitrogen radicals — the 

 ptomains (See Chap. IV). Two of these, the diamines putrescine, XHo (CHs)^ XH;, 

 and cadaverine, XH2(CH2)5 NH2 are of particular interest,*'- because they have been 



'8 Zeit. phvsiol. Chem., 1907 (52), 435. 



" Deut. Arch. klin. Med., 1919 (128) 249. 



'9'^ Quart. Jour. Exp. Phvsiol., 1914 (8). 229. 



»«See Gibson, Quart. Jour. Med., 1907 (1), 29; West and Clarke, Lancet, 

 Feb. 2, 1907; Davis, Lancet, Oct. 26, 1912. 



" Quart. Jour. Med., Oct., 1913. 



*- For discussion of formation and properties of these two ptomains, see 

 Vaughan and Xovy's "Cellular Toxins." 



