TY - JOUR
T1 - Stereospecificity of (+)-pinoresinol and (+)-lariciresinol reductases from Forsythia intermedia
AU - Chu, Alex
AU - Dinkova, Albena
AU - Davin, Laurence B.
AU - Bedgar, Diana L.
AU - Lewis, Norman G.
PY - 1993/12/25
Y1 - 1993/12/25
N2 - 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.
AB - 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.
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M3 - Article
C2 - 8262939
AN - SCOPUS:0027756968
SN - 0021-9258
VL - 268
SP - 27026
EP - 27033
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 36
ER -