CHANGES IN ACTIVITIES OF 5-DEHYDKOQUINATE HYDRO-LYASE AND SHIKIMATE-NADP OXIDOREDUCTASE IN SLICED SWEET POTATO ROOTS1

摘要

Sweet potato roots of variety Norin No. 1 were cut into discs (3×19 mm), which were incubated at 28–29°for 4 days. At 24-hour intervals, activities of 5-dehydroquinate hydro-lyase and shikimate-NADP oxidoreductase in the buffer extracts of discs were estimated. The activities of both enzymes were significantly detected in the fresh root tissues. 5-Dehydroquinate hydro-lyase activity per fresh weight increased by three to four times within 2 days after slicing, and decreased gradually. Shikimate-NADP oxidoreductase activity at the lst-day incubation period was found to be about three times as much as the activity found in the fresh roots, and it remained for 4 days after slicing. The role of these enzymes in polyphenol biosynthesis in the sliced root tissues is discussed. An attempt to detect the enzymic conversion of dehydroquinic acid to quinic acid is also descri