VITAMIN L AND FACTORS U, W, R AND S 



confirmed by the increased growth rates of mice fed proteins rich in 

 strepogenin ; proteins such as egg white that contained little strepo- 

 genin had little growth-promoting activity.^^ 



D. W. Woolley ^^ showed that strepogenin was a peptide of glut- 

 amic acid. He observed that it neutralised the effect of the tomato 

 wilting agent, lycomarasmin, which is elaborated by Fusarium lycoper- 

 sici. On hydrolysis, this substance yields aspartic acid, glycine and 

 pyruvic acid, and is probably a tripeptide of serine, glycine and 

 aspartic acid.^^ D. W. Woolley therefore synthesised serylglycyl- 

 aspartic acid and glycylserylaspartic acid, and showed that they had 

 a wilting action on tomato leaves equal to one-sixth, and one-half to 

 one-quarter the activity of lycomarasmin. Arguing that strepogenin 

 might have glutamic acid in place of the aspartic acid of lycomarasmin, 

 D. W. Woolley synthesised L-serylglycyl-L-glutamic acid and found 

 that it had one-fortieth the activity of strepogenin towards L. helveticus, 

 and antagonised the wilting action of serylglycylaspartic acid. Strepo- 

 genin activity was also observed in glycylserylglutamic acid, alanyl- 

 glycylglutamic acid, glycylalanylglutamic acid and glycylglutamic 

 acid. Serylglycylaspartic acid was antagonistic to the growth-promot- 

 ing activity of strepogenin. The strepogenin activity of seryl glycyl- 

 glutamic acid was confirmed by W. A. Krehl and J. S. Fruton.^^ 



Further investigation showed, however, that lycomarasmin con- 

 tained a new amino acid, a-hydroxyalanine, attached by a common 

 nitrogen atom to the amino group of glycylasparagine.^^ Additional 

 peptides were syiithesised and, of these, a-hydroxy-a-acetylamino- 

 propionylglycylaspartic acid, was as active as lycomarasmin. ^^ 



The position occupied by strepogenin in protein molecules was 

 investigated. 2^ In insulin it apparently occurs at the end of the 

 peptide chain, with glycine as the end group. It occupies a similar 

 position in trypsinogen, but probably not in casein. 



A factor that may be identical with strepogenin was found to be 

 necessary for normal growth and survival of the mealworm, Tenebrio 

 molitor, in addition to eight known vitamins ; it was named vitamin 

 Bj provisionally. 2^ 



References to Section 5 



1. N. Nakahara and F. Inukai, Sci. Papers Inst. Phys. Chem. Research 



Tokyo, 1933, 22, 301 ; 1934, 24, 33 ; W. Nakahara, F. Inukai 

 and S. Kato, Proc. Imp. Acad. Tokyo, 1934, 10, 268. 



2. W. Nakahara, F. Inukai, S. Kato and S. Ugami, Sci. Papers Inst. 



Phys. Chem. Research Tokyo, 1936, 29, 47 ; W. Nakahara, F. 

 Inukai and S. Ugami, ibid., 1935, 28, 152 ; 1937, 31, 42 ; 1938, 

 34, 250; 1939, 36, 312 ; 1940, 38, 24 ; Proc. Imp. Acad. Tokyo, 

 1936, 12, 289 ; 1938, 14, 9 ; Science, 1938, 87, 372 ; 1940, 

 91, 431- 



617 



