Zeta-carotene cis isomers as products and substrates in the plant poly-cis carotenoid biosynthetic pathway to lycopene

The plant carotenoid biosynthetic pathway to cyclic carotenes proceeds via carotene precursors in cis configuration. Involvement of individual isomers was elucidated by genetic complementation of desaturations and in vitro reactions of the corresponding enzyme. Determination of substrate and product...

Full description

Saved in:
Bibliographic Details
Published in:Planta 2005-03, Vol.220 (5), p.785-793
Main Authors: Breitenbach, J, Sandmann, G
Format: Article
Language:English
Subjects:
Agronomy. Soil science and plant productions
beta Carotene - metabolism
Biochemical pathways
Biological and medical sciences
biosynthesis
Capsicum - enzymology
Capsicum annuum
carotene 7,8-desaturase
carotenes
Carotenoids
Carotenoids - biosynthesis
Carotenoids - chemistry
Carotenoids - metabolism
Chemical desaturation
Economic plant physiology
enzyme activity
Enzymes
Fruit - enzymology
Fundamental and applied biological sciences. Psychology
Isomerism
Isomerization
Isomers
lycopene
Lycopersicon esculentum - enzymology
Molecular Structure
Nutrition. Photosynthesis. Respiration. Metabolism
Oxidoreductases - metabolism
phytoene desaturase
plant biochemistry
Plant Leaves - enzymology
Plants
Plasmids
Reaction products
Substrate Specificity
zeta Carotene - chemistry
zeta Carotene - metabolism
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The plant carotenoid biosynthetic pathway to cyclic carotenes proceeds via carotene precursors in cis configuration. Involvement of individual isomers was elucidated by genetic complementation of desaturations and in vitro reactions of the corresponding enzyme. Determination of substrate and product specificity of phytoene and ζ-carotene desaturase revealed that 15-cisphytoene is converted to 9,15,9′-tricis-ζ-carotene with 15,9′-dicis-phytofluene as intermediate by the first desaturase. Prior to a subsequent conversion by ζ-carotene desaturase, the 15-cis double bond of 9,15,9′-tricis-ζ-carotene has to be (photo)isomerized to all-trans. Then, the resulting 9,9′-dicis-ζ-carotene is utilized by ζ-carotene desaturase via 7,9,9′-tricis-neurosporene to 7,9,7′,9′-tetracis-lycopene. Other ζ-carotene isomers that are assumed to be spontaneous isomerization products were not converted, except for the asymmetric 9-cis-ζ-carotene. This isomer is desaturated only to 7,9-dicis-neurosporene resembling a dead-end of the pathway. Prolycopene, the product of the desaturation reactions, is finally isomerized by a specific isomerase to all-trans-lycopene, which is a prerequisite for cyclization to β-carotene. The 5-cislycopene and the 9-cis-and 13-cis-β-carotene isomers detected in leaves are thought to originate independently from cis precursors by non-enzymatic isomerization of their all-trans forms.
ISSN:0032-0935
1432-2048
DOI:10.1007/s00425-004-1395-2