LEUCINE. 141 



d-valine can be obtained as microscopic crystalline leaves. It is 

 rather readily soluble in water and the solution has a faint sweetish taste 

 and at the same time somewhat bitter. The solution has a rotation 

 of (a) D =+6.42. The hydrochloric acid solution (20 per cent) shows, 

 according to FISCHER, a rotation of (o) D = +28.8. The copper salt, 

 which forms leaves which are rather soluble in water, is very easily soluble 

 in methyl alcohol (SCHULZ and WiNTERSTEiN 1 ). 



The phenylisocyanate melts at 147, and on boiling with 20 per cent 

 hydrochloric acid for a short time, it is changed into d-phenylisopropyl 

 hydantoin, which melts at 131-133 C. 



On putrefaction valine yields isobutylamine and iso valeric acid. 

 /-Leucine (aminocaproic acid, or, more correctly, a-aminoisobutylacetic 

 CH 3 CH 3 

 \X 

 CH 



acid), CeHi3N02= CH 2 , is produced from protein substances in 



CH(NH 2 ) 



COOH 



their hydrolytic cleavage by proteolytic enzymes, by boiling with dilute 

 acids or alkalies or by fusing with alkali hydroxides, and by putrefaction. 

 There are also observations that indicate that in the hydrolysis besides 

 the ordinary leucine perhaps also normal leucine may be formed (HECKEL 

 and SAMEC 2 ). 



Because of the ease with which leucine (and tyrosine) are formed 

 in the decomposition of protein substances, it is difficult to decide pos- 

 itively whether these bodies when found in the tissues are constituents 

 of the living body or are to be considered only as decomposition products 

 formed after death. Leucine, it seems, has been found as a normal 

 constituent of the pancreas and its secretion, in the spleen, thymus, and 

 lymph glands, in the thyroid gland, in the salivary glands, in the kidneys 

 and in the liver. It also occurs in the wool of sheep, in dirt from the 

 skin (inactive epidermis), and between the toes, and its decomposition 

 products have the disagreeable odor of the perspiration of the feet. 

 It is found pathologically in atheromatous cysts, ichthyosis scales, pus, 

 blood, liver, and urine (in diseases of the liver and in phosphorus poison- 

 ing) . Leucine often occurs in invertebrates and also in the plant king- 

 dom. On hydrolytic cleavage various protein substances yield different 

 amounts of leucine, as shown in the tables given on pages 106, 107, 115 and 

 125. From the figures, there given, we call attention to the following: 

 EELENMEYER and SCHOFFER obtained 36-45 per cent leucine from the 

 cervical ligament, E. FISCHER and ABDERHALDEN 20 per cent from hsemo- 



1 Zeitschr. f. physiol. Chem., 35. 



2 Heckel, Monatsh. f. Chem., 29; Samec, ibid., 29. 



