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ALTERATION PRODUCTS OF CHLOROPLAST PIGMENTS 



Established Alteration Reactions 



Both the carotenoid pigments"^* •'•'^ '■'■•'• »° and the chlorophyll s"*-'^ 

 undergo isomerization reactions. These reactions yield additional 

 isomeric pigments that are easily separable in the chromatographic 

 columns o 



TIKhen plants are killed under conditions that do not inactivate 

 enzymes^ the chlorophylls often xindergo rapid oxidation with the pro-, 

 duction of additional green pigmentso The fonnation of these oxida- 

 tion products, which is accelerated by enzymes and by autoxidation, 



varies from plant to plant and with the treatment of the plant 

 tissuel>105"^5. 



The oxidation of the chlorophylls in methanol solutions, •w^iich 

 has long been called allomerization of chlorophyll^, has been found 

 to yield a mixture of several pigments. Some of these oxidation pro- 

 ducts are ohromatographically identical with the enzymatic oxidation 

 products of the chlorophylls. 



Chromatographic studies have shown that the methano lysis products 

 of the chlorophylls, long known as the methyl chlorophyllides-^, are 

 readily separable in the sugar columns o These pigments, formed by 

 enzymatic methanolysis in the presence of dilute methanol, are more 

 sorbed than the natural chlorophylls. The chlorophyllides, themselves, 

 formed by hydrolysis of the chlorophylls, are also separable as very 

 stongly sorbed zones in the sugar columns , 



The pheophytins, which are formed when acid solutions remove the 

 magnesium from the chlorophyll molecule, are weakly sorbed in columns 



