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

J Biol Chem. 1993 Dec 25;268(36):27026-33.


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 [4R-3H] and [4S-3H]NADPH, it was found that only the 4 pro-R hydrogen was abstracted for enzymatic hydride transfer.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Lignin / metabolism
  • Magnetic Resonance Spectroscopy
  • Oxidoreductases / metabolism*
  • Plants / enzymology*
  • Stereoisomerism
  • Substrate Specificity


  • Lignin
  • Oxidoreductases
  • lariciresinol reductase
  • pinoresinol reductase