VIII. EFFECTS OF DEFICIENCY IN ANIMALS 



333 



TABLE X— Continued 



phatase^'" and proteolytic enzymes of liver^^^ and blood.'"''- Table X sum- 

 marizes contributions made in studies with enzymes. 



6. Respiratiox 



There is considerable evidence that ascorbic acid exerts an influence on 

 cellular respiration, but little is actually known as to the mechanisms by 

 which the effects are produced. A role as a reducmg agent has frequently 

 been postulated. King^"^ suggested, however, that rather than functioning 

 as a major hydrogen carrier itself ascorbic acid may serve as a regulating 

 and protective agent, possibly for other hydrogen carriers and other enzyme 

 systems. As previoush' mentioned, much evidence has accumulated which 

 shows that the vitamin can stimulate oxidation, particularl}^ that of certain 

 types of amino acids, fatty acids, phospholipids, and pja-uvate. 



Definite progress has been made in partially elucidating a role of ascorbic 

 acid in respiration bj' the discovery of its function in the oxidation of the 

 side chain of tyrosine.-^^- '^^' *^^ As previously mentioned, Sealock and Good- 



390 H. C. Murray, Proc. Soc. Exptl. Biol. Med. 75, 598 (1950). 



3" E. E. Martinson, I. V. Fetsenko, L. Sokolova, V. Solanikova, and Y. Troitskii, 



Bull. soc. chim. biol. 19, 1521 (1937). 

 '« \. Palladin and P. Normark, Biochem. Z. 152, 420 (1924). 

 "3 p. H. Phillips, F. J. Stare, and C. A. Klvehjom, ./. Biol. Chem. 106, 41 (1934). 

 3" A. D'Agata, Atli accad. peloritana, Classe sci. fis. mat. e. not. 49, 224 (1947). 

 3« T. H. Lan and R. P. Sealock, J. Biol. Chem. 155, 483 (1944). 

 396 R. R. Sealock and T. H. Lan, J. Biol. Chem. 167, 689 (1947). 

 3" H. Okuda, Sei-i-kai Med. /. 57, 4 (1938). 



398 G. Torok and L. Xeufeld, Klin. Wochschr. 13, 1205 (1934). 



399 E. Tria, Atti realc accnd. Italia, Mem. classe sci. fis. inal. t. nat. 3, 806 (1942). 

 "0 W. von Pantslienko-Jurewicz and H. Kraut, Biochem. Z. 285, 407 (1936). 



"' D. V. Bori and B. Cera, Quadcrni nutriz. 6, 301 (1939). 

 *" G. Scoz, C. Cattaneo, and M. C. Gabbrielli, Enzymologia 3, 29 (1937). 

 "3 B. Becker and J. S. Friedenwald, Arch. Biochem. 22, 101 (1949). 

 *"* C. G. King, Cold Spring Harbor Symposia Quant. Biol. 7, 137 (1939). 

 *" W. J. Darby, R. H. DeMeio, M. L. C. Bernheim, and F. Bernheim, J. Biol. Chem. 

 158, 67 (1945). 



