VITAMINS 



255 



N=CH 



I I / 



H3C— C C— CH — N 



N-C g ^ 



CH3 O O 



I II II 



,C=C— CH2CH2OP— 0— P- OH 



I 1 



OH OH 



NH-CO(CH2)4-CH— CH^CH, 

 I I 



s s 



Lipothiamide pyrophosphate 



Still another compound, carnitine, has recently been shown by Carter 

 and co-workers to function as a vitamin for a lower animal organism, 

 namely, the larva of the yellow meal worm, Tenebrio niolitor. These 



(CH3)3N+CHoCHOHCH,COO- 

 Carnitine 



larvae will not grow on synthetic diets containing all the previously 

 known vitamins, but require the addition of supplements such as liver 

 or whey. The effective substance was named vitamin Bt. When iso- 



Courtesy of the S. M. A. Corporation. 

 Fig. 9-15. Pantothenic acid deficiency in the rat. These animals were 

 reared on identical diets except that the one on the left received an ade- 

 quate supply of pantothenic acid, while the diet of the other was deficient 

 in this vitamin. 



lated in pure form, it proved to be identical with carnitine, a compound 

 which had long been known as a constituent of meat extract. It is 

 possible that carnitine functions in the larvae as a source of labile methyl 

 groups (p. 344). 



The so-called "antigray-hair factor" may or may not be a definite 

 substance different from the other known vitamins. It is well established 

 that graying of the hair does result from certain nutritional deficiencies 

 in various species of animals, particularly the rat, mouse, dog, and fox. 



