Stereospecificity of (+)-pinoresinol and (+)-lariciresinol reductases from Forsythia intermedia

Alex Chu, Albena Dinkova, Laurence B. Davin, Diana L. Bedgar, Norman G. Lewis

Research output: Contribution to journalArticle

Abstract

Pinoresinol/lariciresinol reductase catalyzes the first known example of a highly unusual benzylic ether reduction in plants; its mechanism of hydride transfer is described. The enzyme was found in Forsythia intermedia and catalyzes the presumed regulatory branch-points in the pathway leading to benzylaryltetrahydrofuran, dibenzylbutane, dibenzylbutyrolactone, and aryltetrahydronaphthalene lignans. Using [7,7′-2H2]-pinoresinol and [7,7′-2H3]lariciresinol as substrates, the hydride transfers of the highly unusual reductase were demonstrated to be completely stereospecific (>99%). The incoming hydrides were found to take up the pro-R position at C-7′ (and/or C-7) in lariciresinol and secoisolariciresinol, thereby eliminating the possibility of random hydride delivery to a planar quinone methide intermediate. As might be expected, the mode of hydride abstraction from NADPH was also stereospecific: using [4A-3H] and [4S-3H]NADPH, it was found that only the 4 pro-R hydrogen was abstracted for enzymatic hydride transfer.

Original languageEnglish (US)
Pages (from-to)27026-27033
Number of pages8
JournalJournal of Biological Chemistry
Volume268
Issue number36
Publication statusPublished - Dec 25 1993
Externally publishedYes

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ASJC Scopus subject areas

  • Biochemistry

Cite this

Chu, A., Dinkova, A., Davin, L. B., Bedgar, D. L., & Lewis, N. G. (1993). Stereospecificity of (+)-pinoresinol and (+)-lariciresinol reductases from Forsythia intermedia. Journal of Biological Chemistry, 268(36), 27026-27033.