268 Essays in Biochemistry 



the biosynthesis of the aromatic amino acids, and presumably the 

 alkaloids and flavonoids derived from them, 24,25 is dependent on several 

 reactions in the metabolism of carbohydrates which either precede, or 

 are unrelated to, the production of acetate. "Intuitively" and on struc- 

 tural grounds this division was foreseen many years ago. 24 



It is a pleasure to acknowledge the contributions, intellectual as well 

 as experimental, of the investigators who have participated in this 

 investigation in our laboratories, Drs. H. T. Shigeura, P. R. Srinivasan, 

 M. Sprecher, and M. Katagiri, as well as the stimulating and pleasant 

 collaboration with Dr. B. D. Davis. I am grateful to Dr. D. Rittenberg 

 for his support and encouragement during the early period of this 

 investigation. Without his generosity it could not have been under- 

 taken. 



We are indebted to Dr. H. S. Isbell for the labeled sugars, and to 

 Dr. G. Ehrensvard for part of the glucose-6-C 14 used in the investiga- 

 tion; to Dr. B. L. Horecker for gifts of sedoheptulose-7-phosphate and 

 sedoheptulose-l,7-diphosphate and for an opportunity to prepare the 

 latter compound in his laboratory; to Mr. W. E. Pricer, Jr., for phos- 

 phoenolpyruvate; and to Dr. C. E. Ballou for D-erythrose-4-phosphate. 



This work was supported by grants from The American Cancer 

 Society (on recommendation of the Committee on Growth of the Na- 

 tional Research Council), the Lederle Laboratories Division of the 

 American Cyanamid Company, the National Institutes of Health, 

 United States Public Health Service, and the Rockefeller Foundation. 



References 



1. B. D. Davis, J. Biol. Chem., 191, 315 (1951); B. D. Davis, in Amino Acid 

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2. J. Baddiley, G. Ehrensvard, E. Klein, L. Reio, and E. Saluste, J. Biol. Ch< m.. 

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3. L. Reio and G. Ehrensvard, Arkiv Kemi, 5, 301 (1953). 



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9. B. L. Horeeker, M. Gibbs, H. Klenow. and P. Z. Smyrniotis, ./. Biol. Chem., 

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