9 



my preliminary experiments had shown this result to be 

 repeatable in N. silvestris. (iv) Distinctly different 

 properties of the isoenzyme pairs for DAHP synthase, 

 chorismate mutase, and anthranilate synthase have been most 

 useful to demonstrate the separate spatial locations. Since 

 DQT and SDH were known to coexist as a plast id- localized 

 bifunctional protein, I thought it likely that the 

 corresponding cytosolic enzymes would be monofunctional . If 

 so, this would be a type of differential property that might 

 allow me to distinguish the two during cell fractionation 

 studies . 



Shikimate biosynthesis and guinate catabolism 

 In monocots, such as Zea mays, there are two 

 dehydroquinases, one is bifunctional with SDH (specific for 

 NADP^) and the other is either bifunctional or stably 

 complexed with a NAD'' specific quinate dehydrogenase (36) . 

 The pathway steps to quinic acid in plants have not yet been 

 rigorously established and may originate from E4P and PEP 

 via DHQ, or from unknown pathways. Quinate has been shown 

 to accumulate in plant vacuoles and to account for at least 

 10%, if not more, of the dry weight of certain plant tissues 

 (2, V. I. Ossipov, personal communications). The quinate 

 catabolic system from fungi (34,35) overlaps the 

 biosynthetic shikimate pathway with several analogous 

 dehydrogenase and dehydratase reactions (Fig. 1-3) . An 



