IV. HIOCIII.MICAL SYSTKMS \'.] 



Production, sales, and vahw of sales \\avv (Iccrcascd coiisidcrahly in llt.")J 

 over 1951, as the following figures show:^ 



/> A.NUNOBKNZOIC AciD AND ItS SaLTS 



19S1 1952 



Production, lb. 191,000 122,000 



Sales, lb. 169,000 90,000 



Value of sales $595,000 $276,000 



The price of tiie acid (I'.S.P.) in. September, H).").'?, was $2.50, and $1.77 

 for 1 lb. technical grade.' 



The important role of p-aminobenzoic acid in the j)foducti()n of folic 

 acid (pteroylgkitamic acid) is mentioned on p. 33. 



IV. Biochemical Systems 



LEMUEL D. WRIGHT and PETER A. TA\URMINA 



The demonstration that a substance is an essential component of a sys- 

 tem which functions as a biological catalyst is perhaps one of the most 

 useful criteria for a \^itamin. Such a relationship has been shown for many 

 of the B vitamins. The relative difficulty of freeing PABA from some of its 

 conjugate forms suggested to Miller and his associates' that PABA may 

 exist in nature in combination with a protein, that is, that it may function 

 as the prosthetic group of some enzyme. A number of crystalline enzj^mes 

 were examined for their PABA content, which was found to range from 13 

 7 per gram of phosphorylase to 130 y per gram of yeast polypeptidase. It is 

 quite apparent from a consideration of the molecular weights usually as- 

 signed to these proteins that the vitamin was present as an impurity, 

 rather than as an integral part of the enzymes studied. 



Wilhams and his coworkers^ investigated a wide variety of proteins, 

 hormones, and viruses and found that in all cases their P.VBA content was 

 too low to be a constituent part of the molecule. 



Despite the negative results obtained thus far in the search for a specific 

 enzyme with which PABA is associated, a number of interesting publica- 

 tions have appeared concerning enzj^matic systems which involve PABA 

 or its conjugates. Cohen and McCiilvery^-^ investigated the enzymatic con- 



» U. S. Tariff Comm. Repls. 175, 36 (1951); 190, 33 (1952). 

 * Oil, Paint and Drug lieptr. Septemljer 14, 1953. 



1 D. R. Miller, J. O. Lampen, and W. H. Peterson, /. Am. Chem. Soc. 65, 2369 (1943) . 



2 R. J. Williams, F. Schlenk, and M. A. Eppright, J. Am. Chem. Soc. 66, 896 (1944). 



3 P. P. Cohen and R. W. Mc-Gilvcry, ./. liiol. Chem. 166, 261 (1946). 

 ' P. P. Cohen and R. W. McGilvery, ./. Biol. Chem. 169, 119 (1947). 

 ' P. P. Cohen and R. W. McGilvery, ./. Biol. Chem. 171, 121 (1947). 



