Cinnamic acid 4-hydroxylase

Gabriac B, Werck-Reichhart D, Teutsch H, Durst F (1991) Purification and immunochar-acterization of a plant cytochrome P450 the cinnamic acid 4-hydroxylase. Arch Biochem Biophys 288(l) 302-309... 

Mizutani M, Ohta D, Sato R (1993) Purification and characterization of a cytochrome P450 (rran -cinnamic acid 4-hydroxylase) from etiolated mung bean seedlings. Plant Cell Physiol 34 481-488... 

Fahrendorf T, Dixon RA (1993) Stress responses in alfalfa (Medicago sativa L.) XVlll Molecular cloning and expression of the elicitor-inducible cinnamic acid 4-hydroxylase cytochrome P450. Arch Biochem Biophys 305(2) 509-515... 

A different approach to investigate active lignification during resistance reactions is provided by the determination of enzyme activities involved in lignin biosynthesis. Resistant plants are expected to be more strongly activated during or immediately preceding the resistance reaction compared to susceptible plants. Thus, phenylalanine ammonia-lyase (PAL) (43-45), cinnamic acid 4-hydroxylase (46), O-methyltransferases (44), and... 

Gravot, A. et al.. Cinnamic acid 4-hydroxylase mechanism-based inactivation by psoralen derivatives cloning and characterization of a C4H from a psoralen producing plant — Ruta graveolens — exhibiting low sensitivity to psoralen inactivation. Arch. Biochem. Biophys., 422, 71, 2004. 

Blount, J.W. et ah, Altering expression of cinnamic acid 4-hydroxylase in transgenic plants provides evidence for a feedback loop at the entry point into the phenylpropanoid pathway. 

Fig. (2). Proposed pathways of SA and 4HBA biosynthesis. Enzymatic steps for which the enzymes have been identified include PAL, CA4H (cinnamic acid 4-hydroxylase), and BA2H (benzoic acid 2-hydroxylase). Taken from Smith-Becker et al., 1998, [55].

Figure 3-4. The general phenylpropanoid pathway. The enzymes involved in this pathway are (a) phenylalanine ammonia lyase (PAL E.C. 4.3.1.5), (b) cinnamic acid 4-hydroxylase (C4H E.C. 1.14.13.11), and (J) 4-coumaric acid CoA ligase (4CL E.C. 6.2.1.12). (a) depicts tyrosine ammonia lyase activity in PAL of graminaceous species. The grey structures in the box represent an older version of the phenylpropanoid pathway in which the ring substitution reactions were thought to occur at the level of the hydroxycinnamic acids and/or hydroxycinnamoyl esters. The enzymes involved in these conversions are (c) coumarate 3-hydroxylase (C3H E.C. 1.14.14.1), (d) caffeate O-methyltransferase (COMT EC 2.1.1.68), (e) ferulate 5-hydroxylase (F5H EC 1.14.13), and (g) caffeoyl-CoA O-methyltransferase (CCoA-OMT EC 2.1.1.104). These enzymes are discussed in more detail in Section 10.

Reichhart, D., Simon, A., Durst, F., Mathews, J.M., and Ortiz de Montellano, P.R., Autocatalytic inactivation of plant cytochrome P-450 enzymes selective inactivation of cinnamic acid 4-hydroxylase from Helianthus tuberosus by 1-aminobenzotriazole, Arch. Biochem. Biophys., 216, 522-529, 1982. 

Yu et al. (2005) evaluated capsaicin biosynthesis in water-stressed hot pepper fruits. The concentration of capsaicin in the placenta of fruits in the water deficit treatment began to increase rapidly 10 DAF. It reached maximum at 30 DAF and was 3.84-fold higher than in the placenta of control treatment plants. In the pericarp, the concentration of capsaicin reached maximum at 50 DAF and was 4.52-fold higher than in the control treatment. PAL activity was higher in the placenta of fruits in the water deficit treatment than in the fruits of control plants at 50 DAF. At 40 or 50 DAF, cinnamic acid 4-hydroxylase (trans-cinnamate-4-monoox-ygenase) (C4H) activity was higher in plants subjected to the water deficit treatment than in control plants. Capsaicinoid synthase (CS) activity 40 DAF was 1.45- to 1.58-fold higher in fruits in the water deficit treatment than in fruits in the control treatment. 

Oxidation of Phenolic Compounds. Phenolic compounds are widespread throughout the plant kingdom and are prevalent in fruits where they are important contributors to color and flavor (46). Phenolic compounds, particularly flavonoids and derivatives of chlorogenic acid, play a crucial role in the development of a number of postharvest disorders through their oxidation to brown compounds that discolor many fruits and vegetables and substantially reduce their quality. A number of enzymes catalyze the biosynthesis or oxidation of phenolic compounds, among them phenylalanine ammonia lyase (PAL), tyrosine ammonia lyase (TAL), cinnamic acid-4-hydroxylase (CA4H), polyphenol oxidase (PPO), and catechol oxidase (CAO). The chemistry... 

Cinnamic acid 4-hydroxylase from Helianthus tuberosus (Jerusalem artichoke) was the first plant P450 to be functionally characterized. CYP73A1 was designated as the first member of the CYP73 family. This cDNA was isolated from an expression library using antibodies raised against the isolated P450 protein (Section 3.5). Cinnamic acid... 

Cinnamic Acid 4-Hvdroxvlase - The p-hydroxylation of cinnamic acid in the biosynthesis of lignins by plants is mediated by a cytochrome P-450 enz3nne.l ° The cinnamic acid 4-hydroxylase of Jerusalem artichoke tubers is preferentially inactivated by 1-aminobenzotriazole in a tlme-and catalysis-dependent manner.The specific inhibition of cytochrome P-450 enzymes in plants provides a possible avenue for the design of new classes of herbicides and other crop-protection agents. 

MIZUTANI, M., OHTA, D., SATO, R., Purification and Characterization of a Cytochrome-P450 (Trans-Cinnamic Acid 4-Hydroxylase) from Etiolated Mung Bean Seedlings, Plant Cell Physiol., 1993, 34, 481-488. 

It shlklmate dehydrogenase, 2t phenylalanine ammonia-lyase, 3> cinnamic acid 4-hydroxylase, 4 SAMI caffeate 3-0-methyltransferase, 5t hy-droxyclnnamatet CoA llgase, 6t "flavanone synthase", 7t chalcone-flavanone isomerase, 8t SAMt 3, 4 -dihydroxyflavonoid 3 0-methyltrans-[Pg.236]

Resveratrol biosynthesis branches from the phenylpropanoid pathway. The resveratrol biosynthesis pathway consists of four enzymesrphenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), 4-coumarate CoA ligase (4CL), and stilbene synthase (STS). The first two enzymes of the pathway, PAL and C4H, convert phenylalanine into /)-coumaric acid. The third enzyme, 4CL, attaches /)-coumaric acid to the pantetheine group of coenzyme-A (CoA) to produce 4-coumaroyl-CoA. The fourth enzyme, STS, catalyzes the condensation of resveratrol from one molecule of 4-coumaroyl-CoA and three molecules of malonyl-CoA, which originate from fatty acid biosynthesis. TAL is homologous to PAL and converts the amino acid tyrosine directly into / -coumaric acid. Methylated resveratrol derivatives of pinostilbene and pterostilbene are produced by resveratrol O-methyltransferase (ROMT) from resveratrol [135] (Figure 10.10). 

Phenylpropanoids are biologically synthesized from phenylalanine as described above. Among them, cinnamic acid is synthesized directly from phenylalanine by phenylalanine ammonia-liase (PAL), and p-hydroxycinnamic acid p-coumaric acid) is synthesized from cinnamic acid by cinnamic acid 4-hydroxylase (C4H, an enzyme in the cytochrome P-450 family).The phenylpropanoid metabolic pathway is important for plants to synthesize lignin, and some phenylpropanoids are seen at junctions of cell wall polysaccharides such as hemicellulose and pectin. 

PAL, phenylalanine ammonia lyase CA4H, cinnamic acid 4-hydroxylase CPR, Cytochrome P450 reductase 4CL, 4-coumaroyl-CoA ligase CA3H, coumaric add 3-hydroxylase COMT, caffeicacid O-methyltransferase SAM, S-adenosyl-methionine HCHL, hydroxycinnamoyl-CoA pAMT, putative aminotransferase AA, amino add KA, Keto add... 

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