<i>Arabidopsis</i>
            cytochrome P450s that catalyze the first step of tryptophan-dependent indole-3-acetic acid biosynthesis

Hull, Anna K.; Vij, Rekha; Celenza, John L.

doi:10.1073/pnas.040569997

Cited by 432 publications

(333 citation statements)

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“…3), through the activity of gene products of the CYP79 gene family, each of which has substrate specificity for different amino acid precursors. For example, within Arabidopsis, the products of CYP79F1 and F2 catalyse the conversion of elongated homologues of methionine to the corresponding aldoximes [45], CYP79B2 and CYP79B3 convert tryptophan to their aldoximes [46] and CYP79A2 convert phenylalanine to its aldoxime [47]. The aldoxime conjugates with cysteine which acts as the sulphur donor, and then cleaved by a C -S lyase [48].…”

Section: Molecular Genetics and Biochemistry Of Glsmentioning

confidence: 99%

Glucosinolates inBrassicavegetables: The influence of the food supply chain on intake, bioavailability and human health

Verkerk¹,

Schreiner

Krumbein

et al. 2009

Molecular Nutrition Food Res

505

413

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Glucosinolates (GLSs) are found in Brassica vegetables. Examples of these sources include cabbage, Brussels sprouts, broccoli, cauliflower and various root vegetables (e.g. radish and turnip). A number of epidemiological studies have identified an inverse association between consumption of these vegetables and the risk of colon and rectal cancer. Animal studies have shown changes in enzyme activities and DNA damage resulting from consumption of Brassica vegetables or isothiocyanates, the breakdown products (BDP) of GLSs in the body. Mechanistic studies have begun to identify the ways in which the compounds may exert their protective action but the relevance of these studies to protective effects in the human alimentary tract is as yet unproven. In vitro studies with a number of specific isothiocyanates have suggested mechanisms that might be the basis of their chemoprotective effects. The concentration and composition of the GLSs in different plants, but also within a plant (e.g. in the seeds, roots or leaves), can vary greatly and also changes during plant development. Furthermore, the effects of various factors in the supply chain of Brassica vegetables including breeding, cultivation, storage and processing on intake and bioavailability of GLSs are extensively discussed in this paper.

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Section: Molecular Genetics and Biochemistry Of Glsmentioning

confidence: 99%

Glucosinolates inBrassicavegetables: The influence of the food supply chain on intake, bioavailability and human health

Verkerk¹,

Schreiner

Krumbein

et al. 2009

Molecular Nutrition Food Res

505

413

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“…CYP79 family members also catalyze the conversion of amino acids to their corresponding aldoximes in the biosynthesis of cyanogenic glucosides (Halkier et al, 1995; Andersen et al, 2000;Nielsen and Møller, 2000) and glucosinolates (Hull et al, 2000;Mikkelsen et al, 2000;Wittstock and Halkier, 2000). In contrast to glucosinolates that are found primarily in the order Capparales, cyanogenic glucosides are widespread in nature and represent an evolutionary ancient trait.…”

Section: Has Glucosinolate Biosynthesis Evolved From An Iaa Biosynthementioning

confidence: 99%

“…The CYP71 clade is the most expanded cytochrome P450 subfamily, because currently 45 members of the CYP71 family have been identified in Arabidopsis (http://ag.arizona.edu/p450). The significance of the CYP71 clade in the recruitment of enzymes of indole and oxime metabolism also is illustrated by the four CYP71C P450s involved in biosynthesis of indole-derived defense compounds DIBOA (2,4-dihydroxy-1,4-benzoxazin-3-one) and DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one) in grasses (Frey et al, 1997) and by the involvement of CYP71B15 in biosynthesis of the indolederived phytoalexin camalexin (Zhou et al, 2000).Overexpression of CYP79B2 and CYP79B3, recently shown to catalyze indole-3-acetaldoxime formation from tryptophan, did not lead to an IAA phenotype (Hull et al, 2000). Similarly, overexpression of any of the four nitrilases in Arabidopsis did not lead to an IAA phenotype under normal conditions (Normanly et al, 1997;Grsic et al, 1998;Grsic-Rausch et al, 2000).…”

mentioning

confidence: 99%

“…It has recently been shown that the cytochromes CYP79B2 and CYP79B3 of Arabidopsis metabolize tryptophan to indole-3-acetaldoxime. This metabolite is often suggested to be the precursor of indole-3-acetonitrile (IAN) in IAA biosynthesis as well as the precursor of thiohydroximates in glucosinolate biosynthesis (Normanly and Bartel, 1999;Hull et al, 2000;Mikkelsen et al, 2000), although neither step has been characterized biochemically. Nitrilases that catalyze the conversion of IAN to IAA are well characterized in Arabidopsis (Bartel and Fink, 1994).…”

mentioning

confidence: 99%

“…In Arabidopsis, at least six related members of the CYP79 family (http://ag.arizona.edu/p450) have been identified. These enzymes probably all catalyze the conversion of amino acid and chain-elongated amino acids to their acetaldoximes (Bak et al, 1998b;Hull et al, 2000;Mikkelsen et al, 2000;Wittstock and Halkier, 2000). The next P450 in the common pathway from tryptophan, CYP83B1, shows 65% amino acid sequence identity to the most closely related P450, CYP83A1 (Paquette et al, 2000).…”

mentioning

confidence: 99%

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CYP83B1, a Cytochrome P450 at the Metabolic Branch Point in Auxin and Indole Glucosinolate Biosynthesis in Arabidopsis

et al. 2001

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Auxins are growth regulators involved in virtually all aspects of plant development. However, little is known about how plants synthesize these essential compounds. We propose that the level of indole-3-acetic acid is regulated by the flux of indole-3-acetaldoxime through a cytochrome P450, CYP83B1, to the glucosinolate pathway. A T-DNA insertion in the CYP83B1 gene leads to plants with a phenotype that suggests severe auxin overproduction, whereas CYP83B1 overexpression leads to loss of apical dominance typical of auxin deficit. CYP83B1 N-hydroxylates indole-3-acetaldoxime to the corresponding aci -nitro compound, 1-aci -nitro-2-indolyl-ethane, with a K m of 3 M and a turnover number of 53 min Ϫ 1 . The aci -nitro compound formed reacts non-enzymatically with thiol compounds to produce an N -alkyl-thiohydroximate adduct, the committed precursor of glucosinolates. Thus, indole-3-acetaldoxime is the metabolic branch point between the primary auxin indole-3-acetic acid and indole glucosinolate biosynthesis in Arabidopsis. INTRODUCTIONApical dominance, cell expansion, vascular differentiation, lateral root and root hair formation, phototropism, and root gravitropism are among the many processes in plants controlled by auxins (Davies, 1995). The level of auxin is regulated by both de novo biosynthesis and reversible and irreversible conjugation to sugars, amino acids, and peptides as well as by degradation. Although the chemical structure of the primary auxin, indole-3-acetic acid (IAA), has been known since the 1930s (Wildman, 1997), not much is known about how plants actually synthesize this essential compound. Plants appear to be capable of synthesizing IAA by both tryptophan-dependent and tryptophan-independent pathways. Classical incorporation studies with radiolabeled compounds have not unambiguously identified the precursors or elucidated the biosynthetic pathway for IAA. (For a recent review of IAA metabolism, see Normanly and Bartel [1999].)Although a number of mutants in IAA metabolic pathways and perception have been described, the genes involved and their biochemical function and physiological relevance have not all been elucidated (reviewed in Bartel, 1997;Normanly and Bartel, 1999). For example, both the rty/sur1/hls3/alf1 (Boerjan et al., 1995;Celenza et al., 1995;King et al., 1995;Lehman et al., 1996) and sur2 mutants are known to accumulate increased levels of free auxin. Identification of the gene products affected and elucidation of the biochemical roles of these proteins should increase our limited knowledge of IAA biosynthesis and regulation.A link between indole glucosinolates and auxin has often been suggested in the literature. Glucosinolates are sulfurcontaining bioactive natural products derived from amino acids and sequestered in vacuoles of cruciferous plants (Halkier, 1999). It has recently been shown that the cytochromes CYP79B2 and CYP79B3 of Arabidopsis metabolize tryptophan to indole-3-acetaldoxime. This metabolite is often suggested to be the precursor of indole-3-acetonitrile (IAN...

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Auxins (Indole Auxins)

Magnus

Kojić‐Prodić

2002

Encyclopedia of Agrochemicals

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The best‐known phytohormones from the auxin family contain the indole ring system substituted at its 3‐position with a short aliphatic side chain ending in a free carboxyl group. Their most common endogenous representative is indole‐3‐acetic acid (IAA). A variety of its ring‐ and side‐chain substituted derivatives have been prepared by chemical means. Indole auxins are universally required for organized growth at the cellular, tissue, and whole‐plant levels; they are widely used in plant tissue culture and for the rooting of cuttings. Native auxins are now mostly analyzed by methods based on mass spectroscopy. Plants synthesize indole auxins by pathways which may, or may not, include the amino acid, tryptophan. When the hormones become temporarily or permanently dispensable, they are conjugated with amino acids, sugars, or myo‐ inositol and metabolized by oxidation and/or decarboxylation. Auxin perception and signal transduction appear to include soluble ′auxin‐binding proteins′ and auxin‐responsive gene expression, but there are many missing links. A wealth of information on the topology of the active site of the, so far putative, auxin receptor(s) may, however, be deduced from the molecular structures of a large series of synthetic compounds with auxin activity, which have been studied by X‐ray crystallography and computational methods.

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Arabidopsis cytochrome P450s that catalyze the first step of tryptophan-dependent indole-3-acetic acid biosynthesis

Cited by 432 publications

References 37 publications

Glucosinolates inBrassicavegetables: The influence of the food supply chain on intake, bioavailability and human health

Glucosinolates inBrassicavegetables: The influence of the food supply chain on intake, bioavailability and human health

CYP83B1, a Cytochrome P450 at the Metabolic Branch Point in Auxin and Indole Glucosinolate Biosynthesis in Arabidopsis

Auxins (Indole Auxins)

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