IV. BIOCHEMICAL SYSTEMS 401 



by much evidence. Andrus et al} and Warren and Rhoads^ found that re- 

 moval of the liver from dogs was followed by a blood prothrombin drop 

 which could not be prevented by administration of vitamin K and bile 

 salts. Warner^ reported that removal of two-thirds of the liver from rats 

 caused a decrease in blood prothrombin. Liver damage from such toxic 

 agents as chloroform also impairs prothrombin formation.'^- ^ Traumatic 

 injury to the liver can cause a marked loss of blood prothrombin.^ Pro- 

 thrombin loss from these causes is not readily alleviated by vitamin K. 

 For other examples of liver damage and prothrombin deficiency, the reader 

 is referred to a review by Ferguson.^" 



In marked contrast to the chick and other species, the dog is reported 

 to utilize methylnaphthoquinone less efficiently than Ki.^' Quick and Col- 

 lentine'^ have proposed that vitamin Ki is a prosthetic group on an enzyme 

 in liver which takes part in the formation of prothrombin. This subject 

 is discussed more fully in Section VIII of this chapter. 



The suggestion has been advanced that vitamin K-active quinones act 

 through their oxidation-reduction powers. ^^ The redox potential values 

 found were 328 for vitamin Ki, 458 for 2-methyl-l ,4-naphthoquinone, 

 and 256 for phthiocol, which are in same general order as the potencies 

 of these compounds. Trenner and Bacher^^ have also reported some stand- 

 ard oxidation-reduction potentials which are of the same order for the 

 compounds mentioned above. Within the same range are found some naph- 

 thoquinones which possess practically no vitamin K activity, so it is evi- 

 dent that potency is not a simple matter of redox activity, yet this is not 

 excluded as a factor in potency. 



Nothing has yet been reported to link vitamin K and its homologs in 

 moderate doses to any body component other than prothrombin. Defi- 

 ciency of the vitamin has no effect on growth until animals become ill be- 

 cause of hemorrhages.^* Lesions or erosions of the chick gizzard lining were 

 observed^*' ^^ but did not prove to be a characteristic symptom of vitamin 



4 W. D. Andrus, J. W. Lord, Jr., and R. A. Moore, Surgery 6, 899 (1939). 



5 R. Warren and J. E. Rhoads, Am. J. Med. Sci. 198, 193 (1939). 



6 E. D. Warner, /. Ex-ptl. Med. 68, 831 (1938). 



7 K. M. Brinkhous and E. D. Warner, Proc. Soc. Exptl. Biol. Med. 44, 609 (1940). 



8 J. L. Bellman, H. R. Butt, and A. M. Snell, ./. Am. Med. Assoc. 115, 1087 (1940). 



9 J. W. Lord, Surgery 6, 896 (1939). 



10 J. H. Ferguson, Ann. Rev. Physiol. 8, 231 (1946). 



" A. J. Quick and G. E. Collentine, Am. J. Physiol. 164, 716 (1951) ; ./. Lab. Clin. Med. 



36, 976 (1950). 

 12 E. L. McCawley and C. Gurchot, Univ. Calif. (Berkeley) Pubis. Pharmacol. 1, 325 



(1940). 

 " N. R. Trenner and F. A. Bacher, J. Biol. Chem. 137, 745 (1941). 

 " H. J. Almquist and E. L. R. Stokstad, /. Biol. Chem. Ill, 105 (1935). 

 15 H. Dam and F. Sch0nheyder, Biochem. J. 28, 1355 (1934). 



