Novel hydrogen peroxide metabolism in suspension cells of Scutellaria baicalensis Georgi

Satoshi Morimoto, Norifumi Tateishi, Tomoko Matsuda, Hiroyuki Tanaka, Futoshi Taura, Naruto Furuya, Nobuaki Matsuyama, Yukihiro Shoyama

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53 Citations (Scopus)

Abstract

We identified a rapid and novel system to effectively metabolize a large amount of H2O2 in the suspension cells of Scutellaria baicalensis Georgi. In response to an elicitor, the cells immediately initiate the hydrolysis of baicalein 7-O-β-D-glucuronide by β-glucuronidase, and the released baicalein is then quickly oxidized to 6,7-dehydrobaicalein by peroxidases. Hydrogen peroxide is effectively consumed during the peroxidase reaction. The β-glucuronidase inhibitor, saccharic acid 1,4-lactone, significantly reduced the H2O2-metabolizing ability of the Scutellaria cells, indicating that β- glucuronidase, which does not catalyze the H2O2 degradation, plays an important role in the H2O2 metabolism. As H2O2-metabolizing enzymes, we purified two peroxidases using ammonium sulfate precipitation followed by sequential chromatography on CM-cellulose and hydroxylapatite. Both peroxidases show high H2O2-metabolizing activity using baicalein, whereas other endogenous flavones are not substrates of the peroxidase reaction. Therefore, baicalein predominantly contributed to H2O2 metabolism. Because β-glucuronidase, cell wall peroxidases, and baicalein pre-exist in Scutellaria cells, their constitutive presence enables the cells to rapidly induce the H2O2-metabolizing system.

Original languageEnglish
Pages (from-to)12606-12611
Number of pages6
JournalJournal of Biological Chemistry
Volume273
Issue number20
DOIs
Publication statusPublished - May 15 1998

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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