Enzymkatalyse in überkritischem Kohlendioxid: Racemattrennung von D,L‐Menthol

Michor, Harald; Gamse, Thomas; Marr, Rolf

doi:10.1002/cite.330690518

Cited by 6 publications

(1 citation statement)

References 7 publications

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“…387 The enzymatic resolution of (±)-menthol rac-92 in supercritical CO 2 has been investigated. 388 A VCD spectroscopic conformational study of (ϩ)-menthol ent-92 has been carried out. 389 (Ϫ)-Menthol 92 is converted into its α--glucopyranoside 183 when it is incubated with lyophilised cells of Saccharomyces cerevisiae in the presence of maltose.…”

Section: Menthanesmentioning

confidence: 99%

Monoterpenoids (mid-1997 to mid-1999)

Grayson

2000

Nat. Prod. Rep.

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In situ RNA hybridization and immunocytochemistry were used to establish the cellular distribution of monoterpenoid indole alkaloid biosynthesis in Madagascar periwinkle (Catharanthus roseus). Tryptophan decarboxylase (TDC) and strictosidine synthase (STR1), which are involved in the biosynthesis of the central intermediate strictosidine, and desacetoxyvindoline 4-hydroxylase (D4H) and deacetylvindoline 4-O-acetyltransferase (DAT), which are involved in the terminal steps of vindoline biosynthesis, were localized. tdc and str1 mRNAs were present in the epidermis of stems, leaves, and flower buds, whereas they appeared in most protoderm and cortical cells around the apical meristem of root tips. In marked contrast, d4h and dat mRNAs were associated with the laticifer and idioblast cells of leaves, stems, and flower buds. Immunocytochemical localization for TDC, D4H, and DAT proteins confirmed the differential localiza-tion of early and late stages of vindoline biosynthesis. Therefore, we concluded that the elaboration of the major leaf al-kaloids involves the participation of at least two cell types and requires the intercellular translocation of a pathway intermediate. A basipetal gradient of expression in maturing leaves also was shown for all four genes by in situ RNA hy-bridization studies and by complementary studies with dissected leaves, suggesting that expression of the vindoline pathway occurs transiently during early leaf development. These results partially explain why attempts to produce vin-doline by cell culture technology have failed. INTRODUCTION The organs forming the plant body consist of several different cell types that are organized in relation to each other and that confer specific functions to the resulting organ. Each cell type emerges from an undifferentiated meristem according to a sophisticated and partially understood developmental program (Sylvester et al., 1996; von Arnim and Deng, 1996). The commitment to differentiate into specialized structures involves the perception by cells in the meristem of a complex array of signals, which communicate cellular age, position in relation to other cells, and hormonal balance. Environmental factors, such as light and temperature, also play a critical role in modulating these signals throughout the process of organogenesis (Bernier, 1988; Dale, 1988; Sylvester et al., 1996). In addition to morphogenesis, developmental processes result in biochemical specialization of cells for the biosyn-thesis and/or accumulation of secondary metabolites, such as phenylpropanoids (Ibrahim et al.

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Section: Menthanesmentioning

confidence: 99%

Monoterpenoids (mid-1997 to mid-1999)

Grayson

2000

Nat. Prod. Rep.

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Enzymatic Catalysis

Aaltonen¹

1999

Chemical Synthesis Using Supercritical Fluids

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Continuous Flow Enzymatic Kinetic Resolution and Enantiomer Separation using Ionic Liquid/Supercritical Carbon Dioxide Media

et al. 2003

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Abstract:The combination of kinetic resolution in ionic liquids (IL) and selective extraction with supercritical carbon dioxide (scCO 2 ) provides a new approach for the separation of enantiomers as exemplified by the lipase-catalyzed esterification of chiral secondary alcohols. Excellent enantioselectivities are achieved upon conversion of alcohols 1a ± e to the corresponding acetates 4a ± e or laureates 5a ± e using various modifications of the lipase from Candida antarctica (CaL-B) in imidazolium-based ionic liquids. The anion of the ionic liquid has a significant influence on the performance of the bio-catalyst with bis(trifluoromethanesulfonamide) [BTA] giving the best results. The acetates 4a ± e can be extracted from the reaction mixture preferentially over the alcohols 1a ± e with scCO 2 under certain conditions, but preparatively useful selectivities would require advanced multi-step extraction procedures. In contrast, efficient separation is possible with relatively simple equipment if alcohols 1a ± e are extracted preferentially from their corresponding laureates 5a ± e. A ™green∫ continuous process for the resolution of racemic alcohols without the use of organic solvents was devised on the basis of these findings.

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Enzymkatalyse in überkritischem Kohlendioxid: Racemattrennung von D,L‐Menthol

Cited by 6 publications

References 7 publications

Monoterpenoids (mid-1997 to mid-1999)

Monoterpenoids (mid-1997 to mid-1999)

Enzymatic Catalysis

Continuous Flow Enzymatic Kinetic Resolution and Enantiomer Separation using Ionic Liquid/Supercritical Carbon Dioxide Media

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