Where is phytoene synthase from?
plastid stroma
The enzyme phytoene synthase is located in the plastid stroma. Lycopene (responsible for tomato fruit coloration) is formed from phytoene via four stepwise dehydrogenations catalyzed by membrane-bound desaturase enzymes in plastids.
Which organisms is the gene for phytoene synthase extracted?
This version only contained the phytoene synthase (Psy) gene from daffodil and the carotene desaturase (CrtI) gene from the bacterium Pantoea ananatis (previously known as Erwinia uredovora).
What are the enzymes produced using daffodil gene?
The genes inserted into the rice genome, originating from daffodil and the bacterium Erwinia uredovora, caused the cells to produce enzymes that convert geranylgeranyl diphosphate into lycopene.
Why is phytoene good for the skin?
Phytoene (/ˈfaɪtoʊiːn/) is a 40-carbon intermediate in the biosynthesis of carotenoids. Accumulation of these carotenoids in the skin may protect the skin by several mechanisms: acting as UV absorbers, as antioxidants, and as anti-inflammatory agents.
What does phytoene synthase do?
Phytoene synthase (PSY) catalyzes the condensation of two geranylgeranyl diphosphate (GGPP) molecules into one phytoene molecule and is the committal step that diverts carbon flux away from competing pathways and toward carotenoid biosynthesis (Hirschberg 2001; Rodríguez-Villalón et al.
Which transgene is present in Golden Rice?
The product of the two carotenoid biosynthesis transgenes used in Golden Rice, phytoene synthase (PSY) and the bacterial carotene desaturase (CRTI), is lycopene, which has a red color.
What does phytoene synthase do in Golden Rice?
Phytoene synthase is the first committed enzyme in carotenoid biosynthesis and it is also a rate-limiting enzyme for carotenoid production in the endosperm (Farré et al., 2013). The phytoene synthase is the first enzymatic step which produces geranylgeranyl diphosphate (GGPP) (Bai et al., 2016).
What is the Colour of lycopene?
red
Lycopene is the red colored pigment abundantly found in red colored fruits and vegetables such as tomato, papaya, pink grapefruit, pink guava and watermelon. This red colored pigment was first discovered in the tomato by Millardet in 1876 [2]. It was later named lycopene by Schunck [2].
What is golden rice Slideshare?
• Golden rice was created by transforming rice with only two β-carotene biosynthesis genes: 1). psy (Phytoene synthase) from daffodil (Narcissus pseudonarcissus) 2). crtI (Carotene desaturase) from the soil bacterium Erwinia uredovora. 7. Figure: Gene construct used to generate Golden Rice-1.
What kind of enzyme is phytoene synthase EC 2.5.32?
Phytoene synthase ( EC 2.5.1.32, prephytoene-diphosphate synthase, 15-cis-phytoene synthase, PSase, geranylgeranyl-diphosphate geranylgeranyltransferase) is a transferase enzyme involved in the biosynthesis of carotenoids. It catalyzes the conversion of geranylgeranyl pyrophosphate to phytoene. This enzyme catalyses the following chemical reaction
What happens when phytoene synthase is silenced in tomato?
Phytoene synthase (Psy), the first step in the carotenoid pathway, converting geranylgeranyl diphosphate (GGDP) into phytoene, has been silenced in tomato fruit, resulting in the inhibition of carotenoid biosynthesis, without apparent altered phenotypes of the plant except sensitivity to photobleaching.
How are lycopene and β-carotene synthesized?
The two represented molecules lycopene and β-carotene are synthesized by geranylgeranyl diphosphate (GGPP) synthase (encoded by CrtE), phytoene synthase (encoded by CrtB ), and phytoene desaturase (encoded by CrtI ).
Which is enzyme catalyzes the phytoene desaturase reaction?
Bacterial CRTI is a bifunctional enzyme that catalyzes both phytoene desaturase and ζ-carotene desaturase reactions. Attempts have been made to produce derivatives of β-carotene, such as astaxanthin, in transgenic plants, since astaxanthin contributes to the red pigmentation of fish and crustacean and is important for human health.