III. BIOCHEMICAL SYSTEM 605 



Pantetheine-4'-P + adenosine-P-P-P ^ Pantetheine- 



4'-P-P-5-adenosine (= dephospho-CoA) + PP 



Dephospho-CoA was then converted to CoA with ATP. 



Pantetheine-4'-P-P-adenosine + ATP pantetheine-4'- 



(2) 

 P-P-5-adenosine-3-P ( = CoA) 



The enzymatic synthetis has been reviewed expertly by NoveUi in the 

 CoA Symposium at the Federation Meeting of 1953.^^'' 



2. The Sulfur-Containing Moiety 



It was early observed that CoA preparations contained sulfur in di- 

 sulfide linkage. ^^'^ The preparations gave a tjqDical purple nitroprusside 

 reaction for SH-compounds, but only after reduction, for example, by treat- 

 ment with cyanide. The preparation in which the presence of pantothenic 

 acid was discovered^^' ^^ contained 1.97% sulfur and 11% pantothenic 

 acid, corresponding to 1.2 moles of sulfur per mole of pantothenic acid. 



Initially, however, so much attention was centered on the evaluation of 

 the presence of pantothenic acid in this coenzyme that little attention was 

 paid to the sulfur-containing part. Eventually, through a number of cir- 

 cumstances, information was gained on the nature of the compound as well 

 as on its linkage to pantothenic acid. Very stimulatory in this respect was 

 the discovery by Williams et al.^^ of a new growth factor for Lactobacillus 

 hulgaricus (LBF). This factor was identified as a pantothenic acid derivative 

 and a fragment of CoA.^*- ^'^ Brown ei al. showed that intact CoA was in- 

 active as their factor.''^ However, CoA could be activated by dephosphoryla- 

 tion with intestinal phosphatase. Very significant was the further observa- 

 tion by Snell's group that the bird liver enzyme, which we had found to be 

 necessary for complete liberation of pantothenic acid from CoA, destroyed 

 LBF activity. By following the lead of these observations on Snell's new 

 factor, we obtained by degradation of CoA with intestinal phosphatase 

 and subsequent chromatography^^ a product containing the pantothenic 

 acid linked to a ninhydrin-reactive sulfur compound which, however, was 

 not cystine, as had previously been tentatively assumed. Chromatograph- 

 ically, this degradation product behaved like LBF. A chromatogram of 

 intestinal phosphatase-treated CoA is shown in Fig. 4. 



3«'' G. D. Novelli, Federation Proc. 12, 675 (1953). 



" F. Lipmanu, N. O. Kaplan, and G. D. Novelli, Federation Proc. 6, 272 (1947). 



38 W. L. Williams, E. Hoff-J0rgensen, and E. E. Snell, /. Biol. Chem. 177, 933 (1949). 



39 G. M. Brown, J. A. Craig, and E. E. Snell, Arch. Biochem. 27, 473 (1950). 



'"' R. A. McRorie, P. M. Masley, and W. L. Williams, Arch. Biochem. 27, 471 (1950). 



