680 . ARTHUR ISAAC KENDALL 



As knowledge of bacteriology has increased, attention has been di- 

 rected to the method of formation and mode of physiological action of 

 bacterial products, derived from protein, from polypeptids, or even amino 

 acids, other than soluble toxins. Some of these substances, as indol, are 

 regarded by certain observers to be indicative *of that condition spoken of 

 as auto-intoxication (Combe, Bahr). Others, as betaimidazole ethylamine, 

 possess physiological activity even in minute amounts, which may have 

 pathological significance. Between these two general groups of substances 

 in all probability lie the specific products of the typhoid bacillus, glanders, 

 paratyphoid, and many others, which are perhaps neither as highly or- 

 ganized chemically as the soluble toxins of the diphtheria or tetanus 

 bacilli, nor as simple as the amins derived from the aromatic amino 

 acids. 



2. General Reactions: The Formation of Phenols, 

 Indol and Indican, Amins 



The types of reactions through which proteins are transformed by 

 bacteria into simpler compounds incidental to their utilization for energy 

 are fairly well established, and inasmuch as certain substances of clinical 

 importance are formed in this manner, they have a real importance in 

 any discussion of bacterial action. It is to be remembered that each 

 kind ol organism utilizes protein or protein derivatives somewhat dif- 

 ferently and characteristically, but in general one or more of the fol- 

 lowing reactions are involved, either successively or simultaneously in 

 the katabolism of proteins: 



1. R.CH 2 .CH>7H 2 .COOH + H: 2 R.CH 2 .CH 2 .COOH + NH 3 . 



Reductive deamination of an amino acid to a fatty acid with 

 the same number of carbon atoms. 



2. R.CH,.CHXII 2 .COOH + H 2 O = R.CH 2 .CHOILCOOH 4- NH 3 . 



Ilydrolytic deamination of amino acid to an oxyacid with the 

 same number of carbon atoms. Lactic acid may be formed 

 from alanin by this process. . 



3. R.CHo.CHNIL.COOH + O = R.CH 2 .CO.COOH + KH,. 



Deamination and simultaneous formation of an alpha ketonic 

 acid. [Pyruvic acid transformation.] 



4. R.CH 2 .CHNH 2 .COOH + O 2 = R.CH 2 .COOII + CO 2 + NH 3 . 



Deamination of amino acid and simultaneous oxidization, re- 

 sulting in a fatty acid with one less carbon atom, 



r>. R.CHo.CHo.COOH > R.CHU.CH, + CO 2 . 



Carboxylic decomposition of fatty acid with the formation 

 of a fatty acid containing one less carbon atom. 



