398 VITAMIN K GROUP 



approximately 1.5,^^ which may mean that Ki is more rapidly absorbed or 

 metabolized than K2 during a short period of time. It is obvious, however, 

 that the long side chains on these vitamins are not specifically required 

 for activity. 



An additional form of vitamin K has been reported in extracts of alfalfa.®" 

 This form did not give the typical strong color reaction in sodium ethylate 

 which has been reported^^ for vitamin Ki yet it showed considerable po- 

 tency.®'' The product was nearly colorless. Vitamin Ki has been converted 

 into a 2,3-oxido derivative, a nearly colorless oil, which gives no color re- 

 action with sodium ethylate and resembles in these respects the second 

 form of vitamin K reported to be in alfalfa.®^ This second form may be one 

 which was reported as existing in the form of relatively colorless crystals 

 at low temperature after isolation from alfalfa. ®- 



Antihemorrhagic activity in the anthraquinone series was investigated 

 briefly by Almquist and Klose,^^ who found no activity in anthraquinone 

 and 1,2-dihydroxyanthraquinone, and by Thayer et aU^ who found none 

 in phenanthraquinone, anthraquinone sulfonic acid, and dihydroanthra- 

 quinone diacetate. Martin and Lischer®^ extended these studies and de- 

 tected very slight activity in 1 , 2 , 4-trihydroxyanthraquinone and certain 

 other polyhydroxyanthraquinones having three hydroxyls on one ring. 

 These workers suggested that such polyhydroxy compounds might be more 

 labile to ring rupture and subsequent formation of 2 , 3-substituted naptho- 

 quinones. 



A few distinct examples of activity are known where conversion to meth- 

 ylnaphthoquinone does not seem possible. 2 , 5-Dimethylbenzoquinone and 

 perhaps certain other substituted benzoquinones have very low but meas- 

 urable activity.®'"®* A degradation product of vitamin E, a-tocopherylqui- 

 none, appears to have slight antihemorrhagic activity.®® It is a benzoqui- 

 none with three methyl groups and a long side chain derived from phytol. 

 This compound is also reported to be antagonistic to vitamin K.®®* Both 

 of these reports may be correct if the a-tocopherylquinone displaces vita- 

 min K from an enzyme system forming another enzyme of very low but 



" S. A. Thayer, R. W. McKee, S. B. Binkley, D. W. MacCorquodale, and E. A. Doisy, 

 Proc. Soc. Exptl. Biol. Med. 41, 194 (1939). 



60 S. Ansbacher, E. Fernholz, and H. B. MacPhillamy, Proc. Soc. Exptl. Biol. Med. 

 42, 655 (1939). 



61 L. F. Fieser, M. Tishler, and W. L. Sampson, /. Am. Chetn. Soc. 62, 1628 (1940). 



62 H. J. Almquist, Nature 140, 25 (1937). 



63 G. J. Martin and C. F. Lischer, /. Biol. Chem. 137, 169 (1941). 

 6* S. Ansbacher and E. Fernholz, /. Biol. Chem. 131, 399 (1939). 



66 H. J. Almquist, Physiol. Revs. 21, 194 (1941). 



66 R. Kuhn, K. Wallenfels, F. Weggand, T. Moll, and L. Hepding, Naturwissenschaf- 



ten 27, 518 (1939). 

 66a D. W. Woolley, J. Biol. Chem. 159, 59 (1945). 



