45 



CHAPTER III 

 PHYSIOLOGICAL PROFILE OF AROIVIATIC PATHWAY ENZYMES IN PLANTS 



The activities of dehydroquinase and shikimate 

 dehydrogenase (of the common portion of aromatic 

 biosynthesis) , and prephenate aminotransferase, arogenate 

 dehydratase and arogenate dehydrogenase (of the post- 

 prephenate portion of the pathway) were examined under 

 selected physiological conditions in the higher plant N. 

 silvestris and in the green alga Chlorella sorokiniana. 

 Prephenate aminotransferase from Chlorella exhibited several 

 of the striking characteristics of higher plant enzyme. 



Arogenate dehydratase activities were followed in a 

 growth culture cycle of N. silvestris suspension cells 

 similarly as was followed for PAT and ADH (12) . 



Results 

 Specific activities from crude extracts 



Specific activities have been compared for several 

 aromatic amino acid pathway enzymes of N. silvestris 

 cultured cells and from the green alga C. sorokiniana (Table 

 3-1) . A constant ratio of about 5 for SDH and DQT activity 

 was found in N. silvestris, compared to a ratio of 1 for 

 crude extracts of C. sorokiniana. The activities of DQT and 



