138 



OXYPROTEIC ACIDS 



urinary coloring matter, uro chrome. Moritz Weiss 54 has 

 shown in the course of his investigations (partly carried out 

 in the Vienna Physiological Institute) that urochrome is 

 produced from a ehromogen, urochromogen, which is like- 

 wise an oxyproteic acid. This chromogen is characterized 

 by two striking peculiarities, viz., by its ability to pass over 

 into urochrome upon oxidation (a faintly tinted yellowish- 

 green solution assuming an intense yellow color when per- 

 manganate of potassium is added drop by drop), and by the 

 interesting fact that it is the particular substance involved 

 in Ehrlieh's curious diazo-reaction. Very shortly after the 

 Polish authors happened upon the fact that autoxyproteic 

 acid will give the well known color reaction with the neces- 

 sary diazo -reagents the relation between urochromogen and 

 the diazo-reaction was determined by Weiss. 



It is therefore apparent that we are dealing with a de- 

 cidedly confusing group of phenomena. In the hope, how- 

 ever, of simplifying the current status of proteic acid 

 f ractionation, the following schema is presented : 55 



PKOTEIC ACID FKACTION 



(The group of substances which form baryta salts which 

 are soluble in water, but precipitated by alcohol.) 



Alloxyproteic Autoxyproteic Acid Oxyproteic Acid 

 Acid Fraction Fraction (precipi- Fraction (precipi- 

 (precipitated by tated by mercuric tated by mercuric 

 acetate of lead) acetate in weakly acetate in soda- 

 acid reaction) alkaline reaction) 



Dombrowski's 

 Urochrome 



Urochromogen 



[transformed by oxidation 



into true urochrome) 



Colorless 



Alloxyproteic 



Acid. 



M M. Weiss (Alland Hosp.), Wiener klin. Wochenschr., 1907, No. 31; Beitr. 

 z. Klinik der Tuberculose, 8, 117, 1907; Biochem. Zeitschr., 27, 175, 1910; 30, 

 333, 1911, under direction of O. v. Furth, Physiol. Instit. Vienna; Med. Klinik, 

 1910, No. 92 ; Miinchener med. Wochenschr., 191 1, No. 25. 



58 M. Weiss, Biochem. Zeitschr., 30, 338, 1911. 



