A novel glucosylation enzyme: Molecular cloning, expression, and characterization of Trichoderma viride JCM22452 α-amylase and enzymatic synthesis of some flavonoid monoglucosides and oligoglucosides

Akio Noguchi, Misa Inohara-Ochiai, Noriko Ishibashi, Harukazu Fukami, Toru Nakayama, Masahiro Nakao

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

It was found that commercial cellulase preparations from Trichoderma viride showed transglucosylation activity toward (+)-catechin and (-)-epigallocatechin gallate (EGCG) using dextrin as a glucosyl donor. To isolate the enzyme exhibiting transglucosylation activity toward (+)-catechin and EGCG, the present study isolated the cDNA encoding the T. viride JCM22452 α-amylase homologue (TRa2), which showed high amino acid sequence identity to functionally uncharacterized R-amylase homologues from other ascomycetes, which also produced some (+)-catechin and EGCG glucosides. TRa2 was able to glucosylate a wide range of natural flavonoids, particularly (+)-catechin and EGCG, and to hydrolyze maltooligosaccharides (kcat/Km for maltotriose, maltotetraose, maltopentaose, maltohexaose, and maltoheptaose were 1.98, 45.2, 58.3, 97.4, and 92.6 s-1 mM-1, respectively) except maltose but could not transfer the monoglucosyl residue to maltooligosaccharides. By 1H NMR and 13C NMR, the structures of several novel glucosides obtained by commercial cellulase preparations from T. viride and TRa2 were determined as (+)-catechin 5-O-α-D-glucopyranoside, (+)-catechin 5-O-α-D-maltoside, (+)-catechin 4′-O-α-D-maltoside, EGCG 5-O-α-D-glucopyranoside, and EGCG 7-O-α-D-maltoside. One of these glucosides, EGCG 5-O-α-D-glucopyranoside, showed higher heat stability and solubility and lower astringency and astringent stimulation than its aglycon, suggesting that EGCG glucosides are functionally superior to EGCG as food additives.

Original languageEnglish
Pages (from-to)12016-12024
Number of pages9
JournalJournal of Agricultural and Food Chemistry
Volume56
Issue number24
DOIs
Publication statusPublished - 2008 Dec 24

Keywords

  • Glucosylation
  • Oligoglucoside
  • Trichoderma viride
  • α-amylase

ASJC Scopus subject areas

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)

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