排序方式: 共有3条查询结果,搜索用时 0 毫秒
1
1.
Wild-type cytochrome P450 monooxygenase from Bacillus megaterium (P450 BM-3) has a low hydroxylation activity for β-ionone (<1 min−1). Substitution of phenylalanine by valine at position 87 led to a more than 100-fold increase in β-ionone hydroxylation activity
(115 min−1). Enzyme activity could be further increased by both site-directed and random mutagenesis. The mutant R47L Y51F F87V, designed
by site-directed mutagenesis, and the mutant A74E F87V P386S, obtained after two rounds of error-prone polymerase chain reaction,
exhibited an increase in activity of up to 300-fold compared to the wild-type enzyme. The triple mutant R47 LY51F F87V exhibited
moderate enantioselectivity, forming (R)-4-hydroxy-β-ionone with an optical purity of 39%. All mutants regioselectively converted β-ionone into 4-hydroxy-β-ionone.
The regioselectivity is determined amongst others by the absolute configuration of the substrate. 相似文献
2.
Cultivation of the fungus Penicillium melinii UzLM-4 on a Raistrick's medium of our own modification made it possible to increase the biosynthesis of lipases three to four times. The following conditions ensured a high rate of synthesis of the extracellular lipase: age of the inoculum, 15 days; concentration of the inoculum, 15 x 10(6) conidia per 100 ml medium; initial pH of the nutrient medium, 8.0; and cultivation in a shaker at 150 rpm (25 degrees C). 相似文献
3.
Makhsumkhanov A. A. Yakubov I. T. Davranov K. 《Applied Biochemistry and Microbiology》2003,39(1):40-43
Cultivation of the fungus Penicillium melinii UzLM-4 on a Raistrick's medium of our own modification made it possible to increase the biosynthesis of lipases by three to four times. The following conditions ensured a high rate of synthesis of the extracellular lipase: age of the inoculum, 15 days; concentration of the inoculum, 15 × 106 conidia per 100 ml medium; initial pH of the nutrient medium, 8.0; and cultivation in a shaker at 150 rpm and 25°C. 相似文献
1