428 PHYSIOLOGICAL CHEMISTRY 



meters of the urine for coagulable protein, by tests 2 and 4 under Albumin, pages 

 424-5. If coagulable protein is present remove it by coagulation and nitration 

 before proceeding. Introduce 25 c.c. of the urine, freed from coagulable protein, 

 into 150 c.c. of absolute alcohol and allow it to stand for 12-24 hours. Decant the 

 supernatant fluid and dissolve the precipitate in a small amount of hot water. Now 

 filter this solution, and after testing again for nucleoprotein with very dilute acetic 

 acid, try the biuret test. If this test is positive the presence of proteose is indicated. 1 



Urobilin does not ordinarily interfere with this test since it is almost entirely 

 dissolved by the absolute alcohol when the proteose is precipitated. 



4. Detection of "Bence-Jones* Protein." Heat the suspected urine very 

 gently, carefully noting the temperature. At as low a temperature as 4oC. a 

 turbidity may be observed, and as the temperature is raised to about 6oC. a 

 flocculent precipitate forms and clings to the sides of the test-tube. If the urine 

 is now acidified very slightly with acetic acid and the temperature further raised 

 to iooC. the precipitate at least partly disappears; it will return upon cooling 

 the tube. 



This property of precipitating at so low a temperature and of dissolving at a 

 higher temperature is typical of "Benee- Jones' protein" and may be used to differ- 

 entiate it from all other forms of protein material occurring in the urine. 



NUCLEOPROTEIN 



There has been considerable controversy as to the proper classifica- 

 tion for the protein body which forms the "nubecula" of normal urine. 

 By different investigators it has been called mucin, mucoid, phospho- 

 protein, nucleo albumin, and nucleoprotein. Of course, according to 

 the modern acceptation of the meanings of these terms they cannot be 

 synonymous. Mucin and mucoid are glycoproteins and hence contain 

 no phosphorus (see page 112), whereas phosphoproteins and nucleo- 

 proteins are phosphorized bodies. It may possibly be that both these 

 forms of protein, i.e., the glycoprotein and the phosphorized type, 

 occur in the urine under certain conditions (see page 396). In this 

 connection we will use the term nucleoprotein. The pathological con- 

 ditions under which the content of nucleoprotein is increased includes 

 all affections of the urinary passages and in particular pyelitis, nephritis, 

 and inflammation of the bladder. 



EXPERIMENTS 



i. Detection of Nucleoprotein. Place 10 c.c. of urine in a small beaker, 

 dilute it with three volumes of water to prevent precipitation of urates, and make 

 the reaction very strongly acid with acetic acid. If the urine becomes turbid 

 it is an indication that nucleoprotein is present. 



* If it is considered desirable to test for peptone the proteose may be removed by satu- 

 ration with (NH 4) 2 SO 4 according to the directions given on p. 120 and the nitrate tested 

 for peptone by the biuret test. 



