A flavoprotein (FAD) that is active under conditions of low light. Along with EC 1.23.5.1, violaxanthin de-epoxidase, this enzyme forms part of the xanthophyll (or violaxanthin) cycle, which is involved in protecting the plant against damage by excess light. It will also epoxidize lutein in some higher-plant species.
A flavoprotein (FAD) that is active under conditions of low light. Along with EC 1.23.5.1, violaxanthin de-epoxidase, this enzyme forms part of the xanthophyll (or violaxanthin) cycle, which is involved in protecting the plant against damage by excess light. It will also epoxidize lutein in some higher-plant species.
the enzyme catalyses the epoxidation of zeaxanthin to antheraxanthin and violaxanthin, generating the epoxycarotenoid precursor of the ABA biosynthetic pathway, overview
the enzyme catalyses the epoxidation of zeaxanthin to antheraxanthin and violaxanthin, generating the epoxycarotenoid precursor of the ABA biosynthetic pathway, overview
the enzyme is important in the xanthophyll cycle and in abscisic acid biosynthesis, abscisic acid is a plant hormone and key molecule that regulates plant responses to abiotic stress, such as drought and salinity, and is required for stress tolerance, overexpression of ZEP leads to increased salt and rought tolerance in transgenic plants, overview
up-regulation of the zeaxanthin epoxidase gene ABA1/ZEP and three 9-cis-epoxycarotenoid dioxygenase genes, NCED2, NCED5, and NCED9 is responsible for suppression of seed germination at supraoptimal high temperature, thermoinhibitIon, during summer to establish vegetative and reproductive growth in appropriate seasons of Arabidopsis thaliana, abscisic acid and gibberellins play a role in the regulation of germination, overview
the enzyme catalyses the epoxidation of zeaxanthin to antheraxanthin and violaxanthin, generating the epoxycarotenoid precursor of the ABA biosynthetic pathway, overview
the enzyme catalyses the epoxidation of zeaxanthin to antheraxanthin and violaxanthin, generating the epoxycarotenoid precursor of the ABA biosynthetic pathway, overview
the enzyme is important in the xanthophyll cycle and in abscisic acid biosynthesis, abscisic acid is a plant hormone and key molecule that regulates plant responses to abiotic stress, such as drought and salinity, and is required for stress tolerance, overexpression of ZEP leads to increased salt and rought tolerance in transgenic plants, overview
up-regulation of the zeaxanthin epoxidase gene ABA1/ZEP and three 9-cis-epoxycarotenoid dioxygenase genes, NCED2, NCED5, and NCED9 is responsible for suppression of seed germination at supraoptimal high temperature, thermoinhibitIon, during summer to establish vegetative and reproductive growth in appropriate seasons of Arabidopsis thaliana, abscisic acid and gibberellins play a role in the regulation of germination, overview
zeaxanthin oxidase is the major contributor to carotenoid composition, with mutants lacking ZEP activity showing a 6fold increase in total seed carotenoids relative to the wild type. Natural variation in ZEP gene expression during seed development is the underlying mechanism for fine-tuning carotenoid composition, stability, and ultimately content in Arabidopsis seed. ZEP acts as an upstream control point of carotenoid homeostasis, with ZEP-mediated epoxidation targeting carotenoids for degradation by carotenoid clevage dioxygenase enzymes
sequence analysis establishes the enzyme as a member of the lipocalin family of proteins, a diverse group of proteins that bind small hydrophobic molecules and share a conserved tertiary structure of eight beta-strands forming a barrel configuration
transgenic Arabidopsis thaliana plants overexpressing the AtZEP gene exhibit more vigorous growth under high salt and drought treatments than wild-type plants. In addition to enhanced de novo abscisic acid biosynthesis, they also exhibit much higher expression of the endogenous stress-responsive genes RD29A and Rab18 than wild-type plants under salt stress, and the stomatal aperture of the AtZEP-overexpressing plants is smaller than wild-type plants after exposure to light, overview
Polyphyletic analyses of the presence of photoprotective compounds and zeaxanthin epoxidase ZE sequences across a wide representation of the plant kingdom reveals no correlation between the presence of lutein-epoxide and recurrent mutations in ZE sequences, including the duplications. There is an evolutionary trend to increase the content of alpha-tocopherol and to decrease the total amount of violaxanthin-cycle pigments.
Polyphyletic analyses of the presence of photoprotective compounds and zeaxanthin epoxidase ZE sequences across a wide representation of the plant kingdom reveals no correlation between the presence of lutein-epoxide and recurrent mutations in ZE sequences, including the duplications. There is an evolutionary trend to increase the content of alpha-tocopherol and to decrease the total amount of violaxanthin-cycle pigments.
New transgenic line of Arabidopsis thaliana with partly disabled zeaxanthin epoxidase activity displays changed carotenoid composition, xanthophyll cycle activity and non-photochemical quenching kinetics