The biosynthesis of cyanogenic glucosides in higher plants. The (E)- and (Z)-isomers of p-hydroxyphenylacetaldehyde oxime as intermediates in the biosynthesis of dhurrin in Sorghum bicolor (L. ) Moench

Journal Article · Sat Nov 25 00:00:00 EST 1989 · Journal of Biological Chemistry; (USA)

OSTI ID:5085711

Halkier, B A; Olsen, C E; Moller, B L ^[1]

---

1. Royal Veterinary and Agricultural Univ., Frederiksberg C (Denmark)

The biosynthesis of the tyrosine-derived cyanogenic glucoside dhurrin has been studied with a microsomal preparation obtained from etiolated seedlings of sorghum. The biosynthetic pathway involves tyrosine, N-hydroxytyrosine, and p-hydroxyphenylacetaldehyde oxime as early intermediates. The use of deuterium-labeled tyrosine and mass spectrometric analyses demonstrate that the alpha-hydrogen atom of tyrosine is retained in the conversion of tyrosine to p-hydroxyphenylacetaldehyde oxime. This excludes p-hydroxyphenylpyruvic acid oxime as intermediate in the pathway. A high pressure liquid chromatography method was developed to separate the (E)- and (Z)-isomers of p-hydroxyphenylacetaldehyde oxime. The microsomal enzyme system was found to produce initially the (E)-isomer of p-hydroxyphenylacetaldehyde oxime. An isomerase then converts the (E)-isomer to the (Z)-isomer, which is the isomer preferentially utilized by the microsomal enzyme system in the subsequent biosynthetic reactions. The (E)-isomer produced in situ is more efficiently converted to the (Z)-isomer than exogenously added (E)-isomer and may thus be metabolically channeled.

• OSTI ID: 5085711
• Journal Information: Journal of Biological Chemistry; (USA), Vol. 264:33; ISSN 0021-9258
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
GLYCOSIDES
BIOSYNTHESIS
BIOLOGICAL PATHWAYS
CARBON ISOTOPES
DEUTERIUM
ISOTOPE DILUTION
LIQUID COLUMN CHROMATOGRAPHY
MASS SPECTRA
MICROSOMES
NITRILES
OXIMES
SORGHUM
TRACER TECHNIQUES
TYROSINE
AMINES
AMINO ACIDS
CARBOHYDRATES
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CEREALS
CHROMATOGRAPHY
GRASS
HYDROGEN ISOTOPES
HYDROXY ACIDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LILIOPSIDA
MAGNOLIOPHYTA
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOIDS
PLANTS
RIBOSOMES
SEPARATION PROCESSES
SPECTRA
STABLE ISOTOPES
SYNTHESIS
550201* - Biochemistry- Tracer Techniques