Dhurrin, biosynthesis

Moller, B.L. and Conn, E.E. (1980) The biosynthesis of cyanogenic glucosides in higher plants channeling of intermediates in dhurrin biosynthesis by a microsomal system from Sorghum bicolor.. Biol. Chem., 255, 3049-56. 

TABLE 3 Rates of Oxidation of L-Tyroslne and the Intermediates In Dhurrin Biosynthesis by Sorghum Microsomea... 

TABLE 4 Simultaneous Incubation of H-Labelled L-Tyroslne With 4c-intermedlates in Dhurrin Biosynthesis in the Presence of Sorghum Mlcrosomes... 

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. 

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 . 

Biosynthesis of dhurrin in sorghum plays an important role as a model system for obtaining further insight into the enzymology and molecular biology of the biosynthesis of cyanogenic glucosides. 

Figure 3.7 Biosynthesis of cyanogenic glucosides. The biosynthetic pathway of cyanogenic glucosides exemplarily is mentioned for dhurrin. The biosynthesis is performed by the two multi-functional cytochrome P450 enzymes and a UDP-glucosyltransferase. All three enzymes are joined together in a metabolon located in the ER-membrane (according to Nielsen et al., 2008).

Halkier, B.A., Lykkesfeldt, J. and Muller, B.L. (1991) 2-Nitro-3-(p-hydroxyphenyl) propionate and ad-l-nitro-2-(p-hydroxyphenyl)ethane, two intermediates in the biosynthesis of the cyanogenic glucoside, dhurrin, in Sorghum bicolor (L.). Moench. Proc. Natl. Acad. Sci., 88, 487-91. 

McFarlane, I.J., Less, E.M. and Corm, E.E. (1975) The in vitro biosynthesis of dhurrin, the cyanogenic glucoside of Sorghum bicolor.. Biol. Chem., 250, 4708-13. 

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