CATABOLISM OF THE a-AMINOACIDS 467 



AMINO HYDRATE OP KETONIC ALDEHYDE ALCOHOL 



ACID IMINO ACID ACID 



R (oxyacid) 

 .OH 



R R 



1 /H +0^ IX H ~ NI *a 

 I \NH 2 Oxidation I \NH 2 Deamidi- 7 Cleav- 



COOH doOH COOH W 



It might well be conceived, too, that the route from leucin to 

 isovalerianic acid may pass through isoamylainine and 

 isoamylic alcohol : 37 



LEUCIN I8OAMYLAMINE ISOAMYLALCOHOL ISOVALERIANIC 



CH, CH 8 



V 



L 



CH, 



CH.NH, 



COOH 



In experiments of Friedmann 38 (conducted in Hofmeis- 

 ters' laboratory) of the homologues of glycocoll the lower 

 members were better utilized by the economy than the higher. 



The catabolism of tyrosin and phenylalanin has been 

 previously dealt with (Vol. I of this series, pp. 46-55, Chem- 

 istry of the Tissues). In this connection it should be stated 

 that parahydroxyphenylethylamine may undergo transition 

 in the economy into parahydroxyphenylacetic acid : 39 



/OH /OH 



C.HK C,HK 



CH, CH, 



CH 2 .NH, COOH. 



87 C. Oppenheimer and Pincussohn, 1. c., p. 707; F. Sachs (G. Embden's 

 Lab., Frankfurt), Biochem. Zeitschr., 27, 27, 1910. 



88 E. Friedmann, Hofmeister's Beitr., 11, 151, 1908. 



39 A. J. Ewins and P. P. Laidlow, Jour, of Physiol., 12, 78, 1910. 



