Phenylalanine Ammonia-Lyase in Sliced Sweet Potato Roots

Effect of Antibiotics on the Enzyme Formation and its Relation to the Polyphenol Biosynthesis

Abstract

A marked rise in the phenylalanine ammonia-lyase activity and the polyphenol synthesis was observed in sliced roots of a sweet potato. The enzyme activity was found to be localized in the root tissue adjacent to the sliced surface. In this region, the synthesis of polyphenols was much higher compared to the inner tissues. When the specific inhibitors for the protein and nucleic acid biosynthesis such as an actinomycin D and blasticidin S were added to the tissues by vacuum infiltration technique, both the development of phenylalanine ammonia-lyase activity and the synthesis of polyphenols were severely prevented. These results suggest the important role of phenylalanine ammonia-lyase in the polyphenol synthesis and de novo synthesis of the enzyme protein molecule in the sliced tissues.