776 URINE. 



The residue of the amino-acids remaining after deamidation can 

 naturally, according to the rule governing the fatty acids, be burned 

 and in certain cases this combustion takes place with the formation of 

 acetone bodies (which see). The fatty acid residue can also be used, be- 

 sides in the synthesis of amino-acids, also in the synthesis of other 

 substances, and in Chapter VII the formation of carbohydrates from 

 amino-acids has been mentioned. 



Among the amino-acids the cystine, or better the cysteine, 



CH 2 .(SH).CH(NH 2 ).COOH, 



show a special behavior. On oxidation in the SH group and splitting 

 off of CO2 (see page 149) it is transformed into a new amino-acid, taurine 

 (H2N)CH2.CH2(S02OH) . Taurine,iwhich when conjugated with cholic acid 

 forms taurocholic acid, occurring in the bile and which is habitually decom- 

 posed in the intestine or other parts of the animal body, can when intro- 

 duced as such into the human body, at least in part, be eliminated in 

 the urine as such or as tauro-carbamic acid, H2N.CO.NH.C2H4.SO20H 

 (SALKOWSKI l ). Otherwise as end-products of the demolition of cystine 

 and taurine an increased elimination of urinary sulphur, sulphuric acid and 

 thiosulphate, have been observed (BLUM, ABDERHALDEN and SAMUELY 2 ). 

 The sulphydryl group of cysteine also serves in the formation of sulpho- 

 cyanide, which is formed from the nitriles, introduced into the animal 

 body, by the HCN (LANG). The loosely combined sulphur of the pro- 

 teins, according to the observations of PASCHELES, in alkaline reaction and 

 body temperature, can be readily transformed, with the cyan alkali into 

 sulphocyanide alkali. The alkali sulphocyanides when ingested are 

 almost quantitatively eliminated in the urine, according to POLLAK. S 



By substituting one of the hydrogen atoms in the NH2 group of 

 normal a-amino-acids by an alkyl radical (methyl) the combustion of the 

 acids of the series C2 and C4 is considerably retarded and almost entirely 

 prevented in the members of the 5 and CG series (FRIEDMANN) . 4 Sar- 

 cosine (methyl glycocoll), (CH 3 )NH.CH 2 .COOH, is not readily burnt, and 

 therefore passes in great part unchanged into the urine, but perhaps also 

 passes in small part into the corresponding uramino-acid, methylhydan- 

 toic add, NH 2 .CO.N(CH 3 ).CH 2 .COOH (SCHULTZEN 5 ), is an example 



1 Ber. d. d. Chem. Gesellsch., 6, and Virchow's Arch., 58. 



2 Blum, Hofmeister's Beitrage, 5; Abderhalden and Samuely, Zeitschr. f. physiol. 

 Chem., 46. 



3 Lang, Arch. f. exp. Path. u. Pharm., 34; Pascheles, ibid.} Pollak, Hofmeister's 

 Beitrage, 2. 



4 Hofmeister's Beitrage, 11. 



6 Ber. d. d. Chem. Gesellsch., 5. See also Baumann and v. Mering, ibid., 8, and 

 E. Salkowski, Zeitschr. f. physiol. Chem., 4. 



