P-71 タバコ培養細胞によるエノン類の生物変換 : 炭素-炭素二重結合の還元を支配する酵素系(ポスター発表の部)

概要

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In the course of the studies on the biotransformation of exogenous substrates by the Nicotiana tabacum cell cultures, we found that the cells catalyze the regioselective and stereospecific reduction of the C=C bond adjacent to the carbonyl group of enones such as verbenone and carvone. By chromatography on a Diethylaminoethyl (DEAE) TOYOPEARL column, two different reductases were isolated from cultured cells of N. tabacum, one responsible for the reduction of verbenone (verbenone reductase) and the other responsible for that of carvone (carvone reductase). Characterization of the verbenone reductase revealed that it reduces enantioselectively the C=C bond of verbenone and slightly that of carvone. In order to investigate the mechanism of the enzymatic reduction, we demonstrated the deuterium incorporation from deuteriated medium (D_2O) and co-enzyme to the substrates and found that verbenone reductase reduces the C=C bond by syn-addition of hydrogen from the re face at β-position and the re face at α-position to the carbonyl group. All of the previous reports on the stereochemistry in the enzymatic reduction of enones have involved reductions occurring by the anti-addition of hydrogen atoms to the C=C bond (the carvone reductase is in such case). The verbenone reductase is unique in the stereochemical aspect of the reduction.
天然有機化合物討論会の論文
1995-09-01