333 Polypeptides and Related Compounds 



microorganisms, although strepogenins (glutamic acid contain- 

 ing oligopeptides from the enzymic digests of certain proteins) 

 stimulate the growth of some bacteria. There is evidence for 

 the occurrence of independent uptake mechanisms for glycine 

 and glycine peptides in Lactobacillus casei.^ 



Glutathione formation takes place in two separate reactions, 

 each involving ATP : - 



( 1 ) L-Glutamic Acid + L-Cysteine + ATP^ 

 L-y-Glutamylcysteine + ADP + H3PO4. 



(2) L-y-Glutamylcysteine + Glycine + ATP^ 

 L-Glutathione + ADP + H3PO4. 



The biosynthesis of pantothenic acid probably proceeds as 

 follows, the last step also being coupled with ATP cleavage, but 

 with different products ■.^- * 



Ci unit from 

 CH3 O tetrahydro- CH3 O 



\ II folic acid | || 



CH— C— COOH > HOCH2— C C— COOH 



CH3 CH3 \ 2H 



a-Ketoisovaleric Acid ^>i 



CH3 

 I 

 HOCH2— C CH— COOH 



^ Franklin R. Leach and Esmond E. Snell, Biochim. et Biophys. 

 Acta 34 292 (1959). 



2 John E. Snoke and Konrad Bloch, /. Biol. Chem. 199 407 (1952); 

 John E. Snoke, ibid. 213 813 (1955); John E. Snoke and Konrad 

 Bloch, ibid. 213 825 (1955); Stanley Mandeles and Konrad Bloch, 

 ibid. 214 639 (1955). 



3 Werner K. Maas and Henry J. Vogel, /. Bacteriol. 65 388 (1953); 

 M. Purko, W. O. Nelson and W. A. Wood, /. Biol. Chem. 207 51 

 (1954); E. Nelson Mcintosh, M. Purko and W. A. Wood, ibid., 228 

 499 (1957). 



* Werner K. Maas, /. Biol. Chem. 198 23 (1952); Akira Matsuyama, 

 Bull. Agr. Chem. Soc. (Japan) 21 47 (1957) and earlier papers in 

 this series; Herbert S. Ginoza and Robert A. Altenbern, Arch. 

 Biochem. and Biophys. 56 537 (1955). 



