Cyanogenic glucoside

In beetles and millipedes, which do not live on plants that produce cyanogenic glycosides, the compound is almost certainly made by the insect or arthropod itself. In millipedes mandelonitrile is stored in an inner chamber of their defensive glands, which is separated from the outer chamber which holds enzymes that catalyze the breakdown of mandelonitrile to benzaldehyde and HCN. A muscle controls the valve between the two chambers. 

The millipede Oxidus gracilis converted racemic [2- C]phenylalanine to HCN, but did not make HCN from [2- C]tyrosine. The steps from phenylalanine to mandelonitrile have been studied in the millipede 

Cyanogenic species are much more common among Lepidoptera, and many of them are able to synthesize the cyanogens. The bright red-and-black bumet moth Zygaena trifolii obtains the cyanogenic glycosides linamirin and lotaustralin from Lotus corniculatus. This species is also 

It is the view of at least one author, L. Kassarov, that the cyanogenic effect has no influence on rejection of butterflies and moths by birds and animals. The release of HCN is too slow to protect the insect. Not even the bitterness of the compounds is responsible, since the compounds are 

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Thiocyanate ion, SCN , inhibits formation of thyroid hormones by inhibiting the iodination of tyrosine residues in thyroglobufin by thyroid peroxidase. This ion is also responsible for the goitrogenic effect of cassava (manioc, tapioca). Cyanide, CN , is liberated by hydrolysis from the cyanogenic glucoside finamarin it contains, which in turn is biodetoxified to SCN. 

These tests demonstrate that rhizomes of johnsongrass have biological activity and that the activity is residual. The allelochemic usually associated with Sorghum species in general, and with johnsongrass in particular, is the cyanogenic glucoside dhurrin (3) or its decomposition product (p-hydroxybenzaldehyde). Whether these compounds act as allelochemics in field situations is unknown and somewhat suspect, since they would surely be immobilized or altered in most soil situations, as was shown for... 

Halkier, B.A., H.V. Scheller, and B.L. Moller. 1988. Cyanogenic glucosides the biosynthetic pathway and the enzyme system involved. Pages 49-66 in D. Evered and S. Harnett (eds.). Cyanide Compounds in Biology. Ciba Foundation Symposium 140. John Wiley, Chichester. 

KOCH, B.M., SIBBESEN, O., HALKIER, B.A., SVENDSEN, I., M0LLER, B.L., The primary sequence of cytochrome P450tyr, the multifunctional N-hydroxylase catalyzing the conversion of L-tyrosine to /7-hydroxyphenylacetaldehyde oxime in the biosynthesis of the cyanogenic glucoside dhurrin in Sorghum bicolor (L.) Moench, Arch. Biochem. Biophys., 1995,323, 177-186. 

CYP79s in the Biosynthesis of Cyanogenic Glucosides and Glucosinolates 233 The Oxime-Metabolizing Enzyme as Branch Point between the Cyanogenic... 

Figure 13.2 Biosynthetic pathways of (A) cyanogenic glucosides and (B) glucosinolates. The CYP79s are assumed to catalyze the same reaction in both pathways. It is not known whether the oxime is oxidized to an aci-nitro compound or a nitrile oxide in the glucosinolate pathway.

Cyanogenic glucosides and glucosinolates are related groups of natural plant products, as both are derived from amino acids and have oximes as intermediates. 

THE OXIME-METABOLIZING ENZYME AS BRANCH POINT BETWEEN THE CYANOGENIC GLUCOSIDE AND THE GLUCOSINOLATE PATHWAY... 

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. 

Tattersall, D. B., Bak, S., Jones, P. R., etal. (2001). Resistance to an herbivore through engineered cyanogenic glucoside synthesis. Science 293,1826-1828. 

For example, the anti (25) and syn (4-hydroxyphenyl)acetaldoximes, 26, are established intermediates in the biosynthesis of the cyanogenic glucoside of sorghum, dhurrin, 27, and the biochemical pathway for its production in the plant was shown to originate in the A -hydroxylation of tyrosine, in the presence of NADPH/O2, as outlined in equation 15". It was further suggested that the Z (syn) isomer, 26, is utilized preferentially over E(anti )-25 in the subsequent biosynthesis of dhurrin, 27. The same authors provided evidence that the biosynthesis of the aldoxime, 25, proceeds via an aci-nitro containing intermediate, R R C=N(0)0H, that is positioned between Af-hydroxytyrosine and anti-25 in the biosynthetic pathway . 

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