30 II. CHEMISTRY OF FATTY ACIDS AND GLYCEROL 



crown-gall bacillus {Phytomonas tumefaciens) ; they designate this acid 

 as phytomonic acid. It is a saturated acid, liquid at ordinary temperature, 

 and has a composition which corresponds to an empirical formula of C20- 

 H40O2. On the basis of the low melting point of 24°C. and of other physical 

 properties, it is believed to be a branched-chain acid.^^^ More recently 

 Velick^^^ suggested that phytomonic acid is either 10- or 1 1-methylnonade- 

 canoic acid. 



g. Other Substituted Acids in Tubercle Bacilli. Ginger and Ander- 

 gQjji54 recently isolated four different dextrorotatory acids from tubercle 

 bacilli which differed from each other in molecular weight and in specific 

 rotation. Phthioic acid, C26H62O2, was included in this group; the composi- 

 tion of the other branched-chain acids corresponded to the empirical 

 formulas of CJ24H48O2, C25H50O2, and C27H64O2. 



h. Unsaturated Substituted Acid. Hilditch and his co-workers^^* 

 demonstrated the presence of a methylated unsaturated odd-carbon acid 

 in the Java "olive" oil from the gum tree (Sterculia foetida). This acid ac- 

 counts for 70% of the total fatty acids in the oil. The acid has been shown 

 to be 12-methyl-9,ll-octadecadienoic acid, which is represented by the 

 formula, CH3(CH2)5C(CH,) :CHCH:CH(CH2)7COOH. 



i. Branched-Chain Fatty Acids in Wool Wax. It has long been known 

 that the lipid make-up of wool wax differs markedly from that of other 

 animal fats. Instead of containing glycerol to serve as the alcohol for 

 combination with the fatty acids, wool fat contains exclusively the mon- 

 atomic alcohols, cholesterol, isocholesterol, and other high aliphatic alco- 

 hols. The major portion of the fatty acids are not combined with these 

 sterols, however, as is indicated by Weitkamp,^ but rather with complex 

 triterpenoid^^^ alcohols which are not found in animal fats.^^^ Weitkamp^ 

 classified the fatty acids present in the following categories: (/) normal 

 saturated acids, (2) 2-hydroxy-acids, (3) iso- (or branched-chain) acids 

 corresponding to the general formula, CH3CH(CH3)(CH2)2«COOH, in 

 which n is 3 to 11 inclusive, and (4) anteiso-acids with the general struc- 

 ture, CH3GH2CH(CH3)(CH2)2«COOH, in which n is 2 to 13 inclusive. 



The normal saturated acids were found to consist of acids with an even 

 number of carbon atoms from 10 to 20. The hydroxy-acids present are 

 described earlier (see page 31). 



The first of the series of homologous iso-acids consist of members with an 

 even number of carbon atoms with the single methyl side chain attached to 

 the penultimate (next to last) carbon atom. It is evident that the fatty 



1" S. F. Velick, /. Biol. Chem., 152, 533-538 (1944). 

 1" S. F. Velick, J. Biol. Chein., 156, 101-107 (1944). 



>6« T. P. Hilditch, M. L. Meara, and Y. A. H. Zaky, J. Soc. Chem. Ind., 60, 198-203 

 (1941). 



«» H. Schulze, Z. physiol. Chem., 238, 35-53 (1936). 



