Manihot esculenta

Until 1987, the (R)-PaHNL from almonds was the only HNL used as catalyst in the enantioselective preparation of cyanohydrins. Therefore, it was of great interest to get access to HNLs which catalyze the formation of (5 )-cyanohydrins. (5 )-SbHNL [EC 4.1.2.11], isolated from Sorghum bicolor, was the first HNL used for the preparation of (5 )-cyanohydrins. Since the substrate range of SbHNL is limited to aromatic and heteroaromatic aldehydes as substrates, other enzymes with (5 )-cyanoglycosides have been investigated as catalysts for the synthesis of (5 )-cyanohydrins. The (5 )-HNLs from cassava (Manihot esculenta, MeHNL) and from Hevea brasiliensis (HbHNL) proved to be highly promising candidates for the preparation of (5 )-cyanohydrins. Both MeHNL and HbHNL have been overexpressed successfully in Escherichia coli, Saccharomyces cerevisiae and Pichia pastoris. 

Figure 8.12 Conversion of benzaldehyde into enantiomerically pure (S)-mandelic acid by the sequential addition of HCN catalyzed by the (.S )-selective oxynitrilase from Manihot esculenta (MeHnL), and subsequent hydrolysis of the resultant (5)-mandelonitrile by the nitrilase from Pseudomonas fluorescens ECB 191 (PfNLase)...

Cassava, Manihot esculenta, roots, total cyanide (mg/kg FW) ... 

Dufour, D.L. 1988. Cyanide content of cassava (Manihot esculenta, Euphorbiaceae) cultivars used by Tukanoan indians in northwest Amazonia. Econ. Botany 42 255-266. 

ANDERSEN, M.D., M0LLER, B.L., Cytochromes P450 from Cassava (Manihot esculenta Crantz) catalyzing the first steps in the biosynthesis of the cyanogenic glucosides linamarin and lotaustralin cloning, functional expression in Pichia pastoris and substrate specificity of the isolated recombinant enzymes, J. Biol. Chem., 2000,275, 1966-1975. 

Jackson LC. 1988. Behavioral effects of chronic sublethal dietary cyanide in an animal model Implications for humans consuming cassava (Manihot esculenta). Hum Biol 60 597-614. 

Kamalu BP. 1993. Pathological changes in growing dogs fed on a balanced cassava (Manihot esculenta Crantz) diet. BR J Nutr 69(3) 921-934. 

Chiral cyanohydrins are versatile intermediates in the synthesis of a-hydroxy acids, /3-amino alcohols, amino nitriles, a-hydroxy ketones and aziridines. For the synthesis of enantiopure cyanohydrins, the use of hydroxynitrile lyases is currently the most effective approach.Application of an organic-solvent-free system allows thermodynamically hindered substrates to be converted with moderate to excellent yields. With the use of the highly selective hydroxynitrile lyase from Manihot esculenta, the syntheses of several acetophenone cyanohydrins with excellent enantioselectivities were developed (Figure 8.2). (5)-Acetophenone cyanohydrin was synthesized on a preparative scale. ... 

Manihot esculenta (manioc) leaves NO 92-124 28.5-30 acetone cyanohydrin HO CN 33, 34... 

More successfully, the (S)-Hnl from Manihot esculenta has also been overexpressed in E. coli [41] and the lysate of the transformed cells showed an enzyme activity of 0.5 units per ml of the culture. A culture of 801 volume of the recombinant MeHnl followed by a short purification procedure [41] yielded 40,000 U. To obtain the equivalent amount of enzyme from the parent plant material would require the processing of 100 -200 kg of dried cassava leaves and thus this recombinant method for the production of MeHnl is a significant practical development. Hence, this recombinant MeHnl has allowed a study of (S)-cyano-hydrin production to be performed [41]. 

Manihot esculenta cytochrome P450 Conversion of vahne and isoleucine to aliphatic aldoximes 103... 

J. Hughes, Z. Keresztessy, K. Brown, S. Suhandono, M. A. Hughes, Genomic organization and structure of % hydroxynitrile lyase in cassava (Manihot esculenta Grantz). Arch. Biochem. Biophys. 1998, 356,107-115. 

Manihot esculenta Crantz. Shu Shu (root) Hydrocyanic acid.76 This herb is toxic. To dress ulcerous sores. 

Gnaphalium affine L., G. multiceps Wall., G. confusum DC, G. luteo-album L. var. multiceps Hook, G. arenarium Thunb., G. ramigerum DC, G. javanum DC, G. uliginosum L., G. tranzschelii Kirpicznikov Manihot esculenta Crantz. 

Acalypha indica, Cydonia oblonga, Hydrangea arborescens, Manihot esculenta, Prunus domestica, P. armeniaca, P. armericana, Sambucus nigra, S. canadensis... 

HNLs from Hevea brasilisensis and Manihot esculenta in the form of economically... 

HNLs are found in over 3000 higher plant species, like Rosaceae, Euphorbiaceae, Linaceae and Filitaceae, in several bacteria, and in some insects [5, 6]. For cyanohydrin synthesis, mainly five HNLs have been used the (R)-selective HNLs from Prunus amygdalus (PaHNL) and Linurn usitatissimum (l.ul INI.) and the (S)-selective ones from Hevea brasiliensis (HfeHNL), Manihot esculenta (MeHNL), and Sorghum bicolor (SfcHNL) [1]. 

Hnl hydroxynitrile lyase Pa Prunus amygdalus Hb Hevea hrasiliensis Sb Sorghum hicolor Me Manihot esculenta. 

F. Effenberger, and K. Pfizenmaier, Enantioselective synthesis of aliphatic (S)-cyanohydrins in organic solvents using hydroxynitrile lyase from Manihot esculenta, Ann. N. Y. Acad. Sci. 1996, 799, 771-776. 

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