52 



SUBCELLULAR PARTICLES 



^2fFig.6 



24 



16 



o p-Benzoquinone 



0.02 M p-Benzoquinone 

 24° C. 75 hrs. 

 Control Solutions 



• — pH 4.3 



■ pH 5.5 



o pH 8.8 



400 450 500 550 600 400 500 



Flu. 6. Visible absorption of p-bcnzoquinone. 

 Fig. 7. Spectra of quinone polymers as related to pH. 



600 



at 500 m/x and which is otherwise grossly different in form. Assuming that 

 a shift of absorption bands toward longer wavelengths accompanies polymeriza- 

 tion, and that a more heterodisperse polymer system will possess a more amor- 

 phous spectrum, it is reasonable to conclude that polymerization, which proceeds 

 with or without fibrin, has been directed by the protein toward formation of a 

 decidedly less heterogeneous array of products. Comparison of the effects of 

 fibrin under acidic and alkaline pH conditions suggests that it only functions 

 well as a matrix in acidic media. At pH 8.8, fibrin would be expected to carry 

 a largely negative charge, and at pH 5.5, a positive charge. More properly, in the 

 mosaic of charged regions comprising the protein surface, negative sites will out- 

 number positive ones at high pH and conversely at low pH. The effect of an 

 immobile ionic surface upon small charged molecules, although generally pre- 

 dictable, was tested specifically by comparison of dye adsorption by fibrin at 

 pH 5.5 and 8.8. Acid fibrin removed methylene blue (cation) from solution, but 

 not eosin (anion), whereas the converse was true for alkaline fibrin. The sig- 

 nificance of this behavior for quinone polymerization derives from the polariza- 

 tion of the carbonyl group (25), a condition which would direct the strongly 

 electronegative cjuinone oxygen atoms toward cationic regions on the matrix, and 

 repel them from anionic sites. The exact mode of quinone orientation will de- 



