Abstract of Dissertation Presented to the Graduate School of 

 the University of Florida in Partial Fulfillment of the 

 Requirements for the Degree of Doctor of Philosophy 



MOLECULAR CHARACTERIZATION OF A BIFUNCTIONAL ENZYME 



(DEHYDROQUINATE DEHYDRATASE/SHIKIMATE DEHYDROGENASE) 



AND THE POST- PRE PHENATE PATHWAY ENZYMES NEEDED FOR 



PHENYLALANINE AND TYROSINE BIOSYNTHESIS IN NICOTIANA SPP, 



By 



Carol Ann Bonner 



April 1994 



Chairman: Roy A. Jensen 



Major Department: Microbiology and Cell Science 



Two bifunctional proteins containing catalytic domains 

 for dehydroquinate dehydratase (dehydroquinase) and 

 shikimate dehydrogenase were separated from extracts of 

 Nicotiana silvestris suspension cells by use of a decreasing 

 ammonium sulfate gradient on a Celite 545 column. The two 

 apparent isoenzymes, denoted as SP-I and SP-II, were 

 purified 1000- and 800-fold, respectively. Higher molecular 

 mass values were obtained for SP-II than for SP-I on the 

 criteria of sodium dodecyl sulfate (SDS) polyacrylamide gel 

 electrophoresis (PAGE) and gel filtration chromatography. 

 Each protein exhibited multiple bands on SDS-PAGE and on 

 native-PAGE monitored with a specific shikimate 



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