Plant hormones are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, from embryogenesis, the regulation of organ size, pathogen defense, stress tolerance and through to reproductive development. Unlike in animals each plant cell is capable of producing hormones. Went and Thimann coined the term "phytohormone" and used it in the title of their 1937 book.
Carotenoids, also called tetraterpenoids, are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, corn, tomatoes, canaries, flamingos, salmon, lobster, shrimp, and daffodils. Carotenoids can be produced from fats and other basic organic metabolic building blocks by all these organisms. The only land dwelling arthropods known to produce carotenoids are aphids, and spider mites, which acquired the ability and genes from fungi. It is also produced by endosymbiotic bacteria in whiteflies. Carotenoids from the diet are stored in the fatty tissues of animals, and exclusively carnivorous animals obtain the compounds from animal fat. In the human diet, absorption of carotenoids is improved when consumed with fat in a meal. Cooking carotenoid-containing vegetables in oil and shredding the vegetable both increase carotenoid bioavailability.
Gibberellins (GAs) are plant hormones that regulate various developmental processes, including stem elongation, germination, dormancy, flowering, flower development, and leaf and fruit senescence. GAs are one of the longest-known classes of plant hormone. It is thought that the selective breeding of crop strains that were deficient in GA synthesis was one of the key drivers of the "green revolution" in the 1960s, a revolution that is credited to have saved over a billion lives worldwide.
Xanthophylls are yellow pigments that occur widely in nature and form one of two major divisions of the carotenoid group; the other division is formed by the carotenes. The name is from Greek xanthos and phyllon, due to their formation of the yellow band seen in early chromatography of leaf pigments.
Abscisic acid (ABA) is a plant hormone. ABA functions in many plant developmental processes, including seed and bud dormancy, the control of organ size and stomatal closure. It is especially important for plants in the response to environmental stresses, including drought, soil salinity, cold tolerance, freezing tolerance, heat stress and heavy metal ion tolerance.
Cytochromes P450 (CYPs) are a superfamily of enzymes containing heme as a cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various compounds, as well as for hormone synthesis and breakdown. In 1963, Estabrook, Cooper, and Rosenthal described the role of CYP as a catalyst in steroid hormone synthesis and drug metabolism. In plants, these proteins are important for the biosynthesis of defensive compounds, fatty acids, and hormones.
The following outline is provided as an overview of and topical guide to biochemistry:
Cholesterol 7 alpha-hydroxylase also known as cholesterol 7-alpha-monooxygenase or cytochrome P450 7A1 (CYP7A1) is an enzyme that in humans is encoded by the CYP7A1 gene which has an important role in cholesterol metabolism. It is a cytochrome P450 enzyme, which belongs to the oxidoreductase class, and converts cholesterol to 7-alpha-hydroxycholesterol, the first and rate limiting step in bile acid synthesis.
In enzymology, a xanthoxin dehydrogenase (EC 1.1.1.288) is an enzyme that catalyzes the chemical reaction
In enzymology, a homoserine dehydrogenase (EC 1.1.1.3) is an enzyme that catalyzes the chemical reaction
7alpha-hydroxycholest-4-en-3-one 12alpha-hydroxylase (EC 1.14.14.139, previously EC 1.14.13.95) is an enzyme that catalyzes the chemical reaction:
In enzymology, a (+)-abscisic acid 8'-hydroxylase (EC 1.14.13.93) is an enzyme that catalyzes the chemical reaction
In enzymology, a kynurenine 3-monooxygenase (EC 1.14.13.9) is an enzyme that catalyzes the chemical reaction
In enzymology, an abscisic-aldehyde oxidase (EC 1.2.3.14) is an enzyme that catalyzes the chemical reaction
In enzymology, an indole-3-acetaldehyde oxidase (EC 1.2.3.7) is an enzyme that catalyzes the chemical reaction
Omega hydroxy acids are a class of naturally occurring straight-chain aliphatic organic acids n carbon atoms long with a carboxyl group at position 1, and a hydroxyl at terminal position n where n > 3. The C16 and C18 omega hydroxy acids 16-hydroxy palmitic acid and 18-hydroxy stearic acid are key monomers of cutin in the plant cuticle. The polymer cutin is formed by inter-esterification of omega hydroxy acids and derivatives of them that are substituted in mid-chain, such as 10,16-dihydroxy palmitic acid. Only the epidermal cells of plants synthesize cutin.
Neoxanthin is a carotenoid and xanthophyll. In plants, it is an intermediate in the biosynthesis of the plant hormone abscisic acid. It is often present in two forms: all-trans and 9-cis isomers. It is produced from violaxanthin, but a suspected neoxanthin synthase is still to be confirmed. Two different genes were confirmed to be implied in violaxanthin conversion to neoxanthin in Arabidopsis and tomato. It has a specific role in protection against photooxidative stress. It is a major xanthophyll found in green leafy vegetables such as spinach.
9-cis-epoxycarotenoid dioxygenase (EC 1.13.11.51, nine-cis-epoxycarotenoid dioxygenase, NCED, AtNCED3, PvNCED1, VP14) is an enzyme in the biosynthesis of abscisic acid (ABA), with systematic name 9-cis-epoxycarotenoid 11,12-dioxygenase. This enzyme catalyses the following chemical reaction
Abscisic aldehyde is an intermediate in the biosynthesis of the plant hormone abscisic acid. It is produced by the dehydrodgenation of xanthoxin by xanthtoxin dehydrogenases, which is an NAD+ dependent short-chain dehydrogenas, followed by selective oxidation by abscisic aldehyde oxygenase.
Cytochrome P450 omega hydroxylases, also termed cytochrome P450 ω-hydroxylases, CYP450 omega hydroxylases, CYP450 ω-hydroxylases, CYP omega hydroxylase, CYP ω-hydroxylases, fatty acid omega hydroxylases, cytochrome P450 monooxygenases, and fatty acid monooxygenases, are a set of cytochrome P450-containing enzymes that catalyze the addition of a hydroxyl residue to a fatty acid substrate. The CYP omega hydroxylases are often referred to as monoxygenases; however, the monooxygenases are CYP450 enzymes that add a hydroxyl group to a wide range of xenobiotic and naturally occurring endobiotic substrates, most of which are not fatty acids. The CYP450 omega hydroxylases are accordingly better viewed as a subset of monooxygenases that have the ability to hydroxylate fatty acids. While once regarded as functioning mainly in the catabolism of dietary fatty acids, the omega oxygenases are now considered critical in the production or break-down of fatty acid-derived mediators which are made by cells and act within their cells of origin as autocrine signaling agents or on nearby cells as paracrine signaling agents to regulate various functions such as blood pressure control and inflammation.
