Glucuronoxylan xylanohydrolase: A unique xylanase with the requirement for appendant glucuronosyl units

K. Nishitani, D. J. Nevins

    Research output: Contribution to journalArticle

    61 Citations (Scopus)

    Abstract

    A new category of β-(1→4)-xylan xylanohydrolases that exhibit a specific capacity to hydrolyze glucuronoxylans was characterized using heteroxylans prepared from Vigna (Vigna angularis Ohwi et Ohashi cv. Takara) and maize (Zea mays L.) cell walls together with appropriate derivatives as substrates. Glucuronopyranosyl moieties, as side chains, were prerequisite for enzyme-mediated hydrolysis of the β-(1→4)-xylosyl linkages. The enzyme degraded glucuronoxylans derived from Vigna cell walls to yield a major oligomeric species where Xyl represents xylose and GlcA represents glucuronic acid. The enzyme also degraded glucuronoarabinoxylans derived from maize cell walls to yield a major oligomeric species containing a single glucuronosyl side chain and a single unsubstituted β1→4Xyl pendant terminal. These results indicate that this xylanohydrolase recognizes glucuronosyl moieties inserted as monomeric side chains along the xylan backbone and mediates the hydrolysis of the β-(1→4)-xylosyl linkage of the adjacent unsubstituted xylosyl residue in heteroxylans. This enzyme is the first xylanohydrolase identified that recognizes distinctly different sugars constituting side chains. We propose to designate this new enzyme as a glucuronoxylan xylanohydrolase to be abbreviated as glucuronoxylanase. Use of this unique enzyme demonstrated the presence of repeating units in heteroxylans in cell walls of higher plants.

    Original languageEnglish
    Pages (from-to)6539-6543
    Number of pages5
    JournalJournal of Biological Chemistry
    Volume266
    Issue number10
    Publication statusPublished - 1991 Jul 23

    ASJC Scopus subject areas

    • Biochemistry
    • Molecular Biology
    • Cell Biology

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