STRl'CTURAL FACTORS IN POI.VM IRl/ATION 



■5/ 



models arose earlier in this investigation when the original hlttr paper matrix 

 system for lignin synthesis was modified by replacement of eugenol and per- 

 oxidase with pyrogallol and Fe(III) respecti\ely. 



PEROXIDASE MODELS AND STEREOSPECIFIC SYNTHESIS 



Pyrogallol Oxidation in the Fe(III)-Biopolymer System. Study of the effect 

 of cellulose was originally directed toward a better understanding of the poly- 

 saccharide matrix, hut developed a second, no less important objective, inves- 

 tigation of the nature of peroxidation reactions. Cellulose affects both the rate of 

 iron-catalyzed peroxidation and the array of products formed (15); its effec- 

 tiveness in increasing the rate of oxidation depends upon the concentration of 

 Fe(III) provided (fig. 11). That the presence of cellulose also modifies the 

 course of pyrogallol oxidation is shown by differences in relative proportions of 

 water- and organic sohent-soluble fractions, particularly in the considerably in- 

 creased chloroform-soluble fraction found when systems without and with filter 

 paper are compared. 



Another biologically important macromolecule capable of enhancing the cata- 

 lytic effectiveness of iron is deoxyribonucleic acid (37), which at very low con- 

 centrations more than doubled the rate of pyrogallol peroxidation measured with 

 Fe(III) alone (fig. 12). Between the two active substances noted were several 

 other macromolecules of varying effect on pyrogallol oxidation with iron, in- 

 cluding fibrin, which promoted, and gelatin and methyl-cellulose, which in- 

 hibited, even at concentrations of the order of io""m. 



In the light of the various systems discussed in connection with the matrix 

 problem, it is not surprising to find those effects described here for cellulose 



Fin. II. Effect of cellulose and Fe(IIIj 

 in rate of pyrogallol oxidation. 



600 



500 



400 



300 



200 



100 



A Substrate 0.1 mmole 



A' Substrate 0.1 mmole + Cellulose 



B Substrate 1.0 mmole 



B' Substrate 1.0 mmole + Cellulose /B' 



Fe(in) Moles x IO"''/20 Ml. 



