TRIGLYCERIDES AND FATTY ACIDS 135 



phlorhizin technic on dogs, that three of the five carbons of L-A-aline d- 

 vahne, and DL-valine can be converted to glucose. In addition, Butts 

 and Sinnhuber^^^ showed that glycogen is deposited in the livers of rats to 

 a small extent following the administration of DL-valine. As a further 

 confirmation of the glucose-forming properties of valine, these latter workers 

 reported that it exerts a ketolytic effect when tested in rats with either 

 exogenous or endogenous ketonuria.''-'' 



Rose and co-workers^-^ postulated that valine is metabolized as illus- 

 trated below: 



CH3 CH3 CH3 CH3 CH3 CH3 



\/ \ / \ / 

 CH CH CH * Glucose 



HCNHo ( > C0=0 COOH 



COOH COOH 



Valine a-Ketoiso- Isobutyric 



valeric acid acid 



The Intermediate Reactions in the Transformation of Valine to Ghicose^^^ 



In further confirmation of the glucose-forming action of valine. Rose et 

 al.^'^^ proved that a-ketoisovalerate, (CH?)2:CII-C0-C00H, is converted 

 to glucose by the phlorhizinized dog to the same extent as is valine, i.e., 

 three of its five carbon atoms are changed. Moreover, Ringer, Frankel, 

 and Jonas^^^ reported that the second postulated intermediate in the 

 valine -^ glucose reaction, namely isobutyric acid, (CH3)2:CH-COOH, is 

 transformed to glucose to the extent of 3 carbons. 



e'. Isovaline: Although there are no data on the ketogenic activity of 

 DL-isovaline, CH3-CH2-C(CH3)(NH2) -COOH, Butts and Sinnhuber324 

 reported that it is devoid of glycogenic activity. 



i' . Tyrosine and Phenylalanine: Baer and Blum^-^ reported that both 

 tyrosine, HO • C4H4 • CH2-CH(NH2) • COOH, and phenylalanine, CeHs- CHj-- 

 CH(NH2) -COOH, are ketogenic under certain conditions. Moreover, 

 Embden and co-workers'' found that not only were tyrosine and phenylal- 

 anine converted to ketone bodies when perfused through a surviving liver, 

 but homogentisic acid, (HO)2-C6H3-CH2-COOH, also, followed the same 

 course of metabolism. Muconic acid, HOOC-CH:CH-CH:CH-COOH, 

 which presumably is an intermediate in the phenylalanine — »- (8-hydroxy- 

 butyrate reaction, likewise yields ketone bodies when perfused through a 



324 J. S. Butts and R. O. Sinnhuber, ./. Biol. Chem., 139, 963-969 (1941). 

 »25 A. I. Ringer, E. M. Frankel, and L. Jonas, /. Biol. Chem., U, 525-538 (1913). 

 32^ J. Baer and L. Blum, Xmmyn-Schmiedeberg' s Arch, exptl. Pathol, Pharmakol., 56, 

 92-100 (1907). 



