236 PYRIDOXINE AND RELATED COMPOUNDS 



lating the hydroxyphenylalanines or hydroxyphenylserines may be of sig- 

 nificance in the formation of arterenol and epinephrin and may bear a rela- 

 tion to hypertension.'*' ^^ 



C. TRANSAMINASES 



These enzymes''^- ^^ catalyze the exchange of amino groups between a- 

 ketoglutarate and a variety of amino acids yielding glutamate and the cor- 

 responding keto acid. The reactions between glutamate and pyruvate to 

 yield alanine and that from glutamate to oxaloacetate to yield aspartate 

 are reversible. These reactions have recently been extended to a variety of 

 other amino acids (listed below), ^^' ®° but these have not yet been shown to 

 be strictly reversible. It would appear, however, that transamination may 

 serve as a general mechanism for the synthesis of amino acids from their 

 keto analogs. Tissues from pyridoxine-deficient animals are low in trans- 



" W. W. Umbreit and I. C. Gunsalus, /. Biol. Chem. 159, 333 (1945). 



38 O. Schales, V. Mims, and S. S. Schales, Arch. Biochem. 10, 455 (1946). 



33 O. Schales and S. S. Schales, Arch. Biochem. 11, 155 (1946). 



" E. Roberts and S. Frankel, /. Biol. Chem. 188, 789 (1951). 



" E. Roberts and S. Frankel, /. Biol. Chem. 190, 505 (1951). 



^2 S. R. Mardasheu and V. N. Gladkoua, Biokhimiya 13, 315 (1948); [C. A. 42, 8859 



(1948); 43, 1073 (1949)]. 

 " D. Billen and H. C. Lichstein, J. Bacteriol. 58, 215 (1949). 

 " W. E. David and H. C. Lichstein, Proc. Sac. Exptl. Biol. Med. 73, 216 (1950). 

 « A. Meister, H. A. Sober, and S. V. Tice, /. Biol. Chem. 189, 577 (1951). 

 " E. F. Gale and H. M. R. Epps, Biochem. J. 38, 232 (1944). 



^^ P. Holtz, R. Heise, and K. Ludtke, Arch. Exptl. Pathol. Pharmakol. 191, 87 (1938). 

 *8 P. Holtz, A. Reinhold, and K. Credner, Z. physiol. Chem. 261, 278 (1939). 

 •*9 P. Holtz, K. Credner, and A. Reinhold, Arch. Exptl. Pathol. Pharmakol. 193, 688 



(1939). 

 ^o P. Holtz and K. Credner, Arch. Exptl. Pathol. Pharmakol. 199, 145 (1942). 

 " P. Holtz, Naturwissenschaften 27, 725 (1939). 



52 H. Blaschko, /. Physiol. (London) 101, 337 (1942). 



" O. Schales and S. S. Schales, Arch. Biochem. 24, 83 (1949). 



"E. W. Page, Arch. Biochem. 8, 145 (1945). 



" D. E. Green, L. F. Leloir, and V. Nocito, /. Biol. Chem. 161, 559 (1945). 



^'5 H. Blaschko, Biochim. et Biophys. Acta 4, 130 (1950). 



" H. Blaschko, Biochem. J. 36, 571 (1942). 



58 F. Bernheim and M. L. C. Bernheim, J. Biol. Chem. 127, 695 (1939). 



53 G. H. Sloane Stanley, Biochem. J. 45, 556 (1949). 

 «" G. Schapita, Compt. rend. soc. biol. 140, 174 (1946). 



" R. W. McGilvery and P. P. Cohen, J. Biol. Chem. 174, 813 (1948). 



^2 P. P. Cohen, Transaminases: A Symposium on Respiratory Enzymes, p. 210. 



University of Wisconsin Press, Madison, Wisconsin, 1942. 

 *3 P. P. Cohen, in The Enzymes, Vol. 1, Part 2, p. 1040. Academic Press, New York, 



1951. 

 " P. S. Cammarata and P. P. Cohen, /. Biol. Chem. 187, 439 (1951). 

 65 L. I. Fcldman and I. C. Gunsalus, ,/. Biol. Chem. 187, 821 (1950). 



