TRIGLYCERIDES AND FATTY ACIDS 77 



Pheiiylmethylcarbinol is reported to be excreted as the glucuronate. 

 On the basis of these results, Quick ^^ states that "Therefore neither phenyl- 

 ;S-hydroxypropionic acid nor acetophenone appears to be a normal inter- 

 mediate in the catabolism of phenylpropionic acid." 



It was reported by Quick^^ that mandelic acid (C6H5 • CHOH • COOH) is 

 neither oxidized nor conjugated by the dog, but is excreted unchanged. 

 This latter finding is in harmony with the results of Knoop,* although the 

 latter worker had not investigated whether or not the end-products of 

 oxidation of mandelic acid were excreted as glucuronates. 



The formation of ketone bodies from the fatty acids having an even 

 number of carbon atoms is another proof of the /3-oxidation theory. Thus, 

 when butyric acid was fed to fasting rats as the sodium salt, ;S-hydroxy- 

 butyrate (CHs- CHOH- CH2- COOH) and acetoacetate (CHs-CO-CHj-- 

 COOH) were excreted in the urine, exemplifying an oxidation on the /3- 

 carbon atom.-^ 



CH3 • CHo • CH2COOH > CH3 ■ CO • CH2 ■ COOH , CH3 • CHOH • CH, • COOH 



Butyric acid Acetoacetic acid /3-Hydroxybutyric acid 



The Relationship between Butyric Acid and the Oxytetranoic Acids 



The formation of acetone, which occurs concomitantly, results from the 

 decarboxylation of acetoacetic acid, as follows: 



CHa-CO-CHs-COOH > CH3COCH3 + CO2 



Acetoacetic acid Acetone 



The Transformation of Acetoacetic Acid to Acetone 



Moreover, an amount of the ketone bodies identical with that obtained 

 following an isomolecular dose of butyrate originated when caproic acid-^-^^ 

 or sorbic acid (CHs-CHiCH-CHiCH-COOH)^^ ^^as given to fasting rats; 

 this must likewise indicate a removal of two carbons. Moreover, all 

 even-chain acids from C4 to Cis were shown to give rise to ketone bodies 

 when fed either as their sodium salts'^ or as their ethyl esters.-^ 



Had only one carbon atom at a time been removed from the even- 

 numbered fatty acids, instead of two carbons, an acid with an uneven 

 number of carbon atoms would have resulted. There is considerable 

 e\ddence that the fate of the odd-carbon acids is entirely different from 

 that of the even-carbon acids. In the first place, whereas all even-carbon 



2' J. S. Butts, C. H. Cutler, L. Hallman, and H. J. Deuel, Jr., /. Biol. Chem., 109, 597- 

 613 (1935). 



" H. J. Deuel, Jr., C. E. Calbert, L. Anisfeld, H. McKeehan, and H. D. Blunden, 

 Food Research, 19, 13-19 (1954). 



" H. J. Deuel, Jr., L. F. Hallman, J. S. Butts, and S. Murray, /. Biol. Chem., 116, 621- 

 639 (1936). 



