Cinnamate-4-hydroxylase/cinnamic acid

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... 

The PAL activity that is necessary for lignin formation occurs in the cytoplasm or bound to the cytoplasmic surface of the endoplasmic reticulum membranes. The cinnamic acid produced is probably carried on the lipid surface of the membranes, since it is lipophilic, and it is sequentially hydroxylated by the membrane-bound hydroxylases (47,50). In this way there is the possibility of at least a two-step channeling route from phenylalanine to p-coumaric acid. The transmethylases then direct the methyl groups to the meta positions. There is a difference between the transmethylases from angiosperms and those from gymnosperms, since with the latter... 

The chemical and physical evidence for the presence of lignin in the material deposited at wound margins is supported by biochemical studies on the enzymes involved in phenylpropanoid metabolism. Thus, the extractable activities of phenylalanine ammonia-lyase, tyrosine ammonia-lyase, cinnamate-4-hydroxylase, caffeic acid O-methyltransferase,... 

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.

The biosynthetic pathway for salicylic acid is not clear. At present, at least two pathways have been proposed. Each branches from phenyl-propanoid biosynthesis after phenylalanine has been converted to trans-cinnamic acid by phenylalanine ammonium lyase (PAL). In one scheme (Pathway 1 Fig. 4), tram-cinnamic acid would be converted to 2-hydroxy cinnamic acid (or 2-coumaric acid) by a cinnamate 2-hydroxylase. This compound could then be converted to salicylic acid via -oxidation possibly through an acetyl coenzyme A (CoA) intermediate. Alternatively, tram-cinnamic acid could be oxidized to benzoic acid and then hydrox-ylated via a postulated o-hydroxylase activity. The details of this pathway, particularly in tobacco and cucumber, deserve further study. 

Cinnamic acid hydroxylase Cyclic AMP phosphodiesterase Diamine oxidase... 

Benveniste, I., Salaun, J.P., and Durst, R, Wounding-induced cinnamic acid hydroxylase in Jerusalem artichoke tuber, Phytochemistry, 16, 69-73, 1977. 

Durst, F., The correlation of phenylalanine ammonia-lyase and cinnamic acid-hydroxylase activity changes in Jerusalem artichoke tuber tissues, Planta, 132, 221-227, 1976. 

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. 

Nair, P.M. and Vrnrng, L.C. (1965) Cinnamic acid hydroxylase in spinach. Phytochemistry, 4,161-8. 

Phenylalanine ammonia-lyase (PAL) eliminates the amino group from phenylalanine (12) to produce cinnamic acid (13). Cinnamate-4-hydroxylase (C4H) hydroxidizes compound (13) to yield p-coumaric acid (14). 4-CoumaroyhCoA-ligase (4CL) complex catalyzed the conversion of p-coumaric acid (14) and coenzyme A (CoA) to 4-coumaroyl-CoA (15) and 3 moles malonyl-CoA (16). Stilbene synthase (STS) converts these two compounds (15,16) into resveratrol of stilbene (7) (Fig. 3) [23,24],... 

L-Phenylalanine,which is derived via the shikimic acid pathway,is an important precursor for aromatic aroma components. This amino acid can be transformed into phe-nylpyruvate by transamination and by subsequent decarboxylation to 2-phenylacetyl-CoA in an analogous reaction as discussed for leucine and valine. 2-Phenylacetyl-CoA is converted into esters of a variety of alcohols or reduced to 2-phenylethanol and transformed into 2-phenyl-ethyl esters. The end products of phenylalanine catabolism are fumaric acid and acetoacetate which are further metabolized by the TCA-cycle. Phenylalanine ammonia lyase converts the amino acid into cinnamic acid, the key intermediate of phenylpropanoid metabolism. By a series of enzymes (cinnamate-4-hydroxylase, p-coumarate 3-hydroxylase, catechol O-methyltransferase and ferulate 5-hydroxylase) cinnamic acid is transformed into p-couma-ric-, caffeic-, ferulic-, 5-hydroxyferulic- and sinapic acids,which act as precursors for flavor components and are important intermediates in the biosynthesis of fla-vonoides, lignins, etc. Reduction of cinnamic acids to aldehydes and alcohols by cinnamoyl-CoA NADPH-oxido-reductase and cinnamoyl-alcohol-dehydrogenase form important flavor compounds such as cinnamic aldehyde, cin-namyl alcohol and esters. Further reduction of cinnamyl alcohols lead to propenyl- and allylphenols such as... 

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... 

Cinnamate 4-hydroxylases catalyze the hydroxylation of frans-cinnamic acid into trans-p-coumaric acid. The ability to monitor this enzyme activity in Jerusalem artichoke allowed isolation of the P450 enzyme CYP73A1 using conventional chromatography and generation of specific antibodies . ... 

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