Protocatechuic

On fusion with potash protocatechuic acid is formed. ... 

It was first artificially prepared by Tiemann from the glucoside coni-ferin, which occurs in the cambium of various coniferous woods. The constitution of vanUlin is that of methyl protocatechuic aldehyde—... 

This body, also known as piperonal, is a white crystalline compound possessing a powerful odour of heliotrope. It is the methylene eEier of protocatechuic aldehyde, of the constitution—... 

Proto-cocasaure,/. protococaic add. -katechu-saure,/. protocatechuic add. 

Studies by Hudson et al, (2000) have demonstrated the presence of eight polyphenols in rice bran by using high-pressure liquid chromatography. They are protocatechuic acid, p-coumaric acid, ferulic acid, sinapic aci vanillic acid, caffeic acid, which is a methoxycirmamic acid derivative, and tricin. The effect of these polyphenols on cell viability and on the colony-forming ability of human-derived MDA MB 468 and HBL 100 breast cells, colon-derived SW 480 and human colonic epithelial cells was assessed. These authors concluded that rice bran polyphenols have putative cancer chemopreventive properties. 

The total phenolic content in XRPP was 1.10%. The major components were found to be p-hydroxybenzoic acid (0.44%), vanillin (0.19%), syringic acid (0.13%), and syringaldehyde (0.13%). The contents of p-hydroybenzaldehyde, vanillic acid and ferulic acid were 0.032, 0.015 and 0.020%, respectively. Gallic acid, protocatechuic acid and cinnamic acid were detected in trace amounts. 

Rhizobia. Taxa belonging to both the genera Rhizobium and Bradyrhizobium are capable of degrading simple aromatic compounds including benzoate (Chen et al. 1984) and 4-hydroxy-benzoate (Parke and Omston 1986 Parke et al. 1991). It has been shown that 4-hydroxyben-zoate hydroxylase is required for the transport of 4-hydroxybenzoate into the cell (Wong et al. 1994). In strains of Rhizobium trifolium, the metabolism of benzoate involves either 3,4-dihydroxybenzoate (protocatechuate) 3,4-dioxygenase (Chen et al. 1984), or catechol... 

Buchan A, LS Collier, EL Neidle, MA Moran (2000) Key aromatic-ring-cleavage enzyme, protocatechuate 3,4-dioxygenase, in the ecologically important marine Roseobacter lineage. Appl Environ Microbiol 66 4662-4672. 

Iwagami S, K Yang, J Davies (2000) Characterization of the protocatechuate acid catabolic gene cluster from Streptomyces sp. strain 2065. Appl Environ Microbiol 66 1499-1508. 

Bull C, DP Ballou (1981) Purification and properties of protocatechuate 3,4-dioxygenase from Pseudomonas putida. A new iron to subunit stoichiometry. 7 Bio/ Chem 256 12673-12680. 

Classic studies were devoted to the regulation of the enzymes for conversion of catechol and 3,4-dihydroxybenzoate (protocatechuate) to 3-ketoadipate by Pseudomonas putida (Ornston 1966),... 

Nichols NN, CS Harwood (1997) PcaK, a high-affinity permease for the aromatic compounds 4-hydroxyben-zoate and protocatechuate from Pseudomonas putida. J Bacteriol 179 5056-5061. 

Ornston LN (1966) The conversion of catechol and protocatechuate to [5-ketoadipate by Pseudomonas putida. IV. Regulation. J Biol Chem 241 3800-3810. 

Crawford RL (1975b) Novel pathway for degradation of protocatechuic acid in Bacillus species. J Bacteriol 121 531-536. 

Wolgel SA, JE Dege, PE Perkins-Olson, CH Juarez-Garcia, RL Crawford, E Mtinck, JD Lipscomb (1993) Purification and characterization of protocatechuate 2,3-dioxygenase from Bacillus macerans a new extradiol catecholic dioxygenase. J Bacterial 175 4414-4426. 

Gorny N, B Schink (1994b) Anaerobic degradation of catechol by Desulfobacterium sp strain cat2 proceeds via carboxylation to protocatechuate. Appl Environ Microbiol 60 3396-3400. 

Priefert H, J Rabenborst, A Steinbuchek (1997) Molecular characterization of genes of Pseudomonas sp. strain HR199 involved in bioconversion of vanillin to protocatechuate. J Bacteriol 179 2595-2607. 

Segura A, PV Biinz, DA D Argenio, LN Ornston (1999) Genetic analysis of a chromosomal region containing van A and van B, genes required for conversion of either ferulate or vanillate to protocatechuate in Acinetobacter. J Bacterial 181 3494-3504. 

Aromatic acids p-Hydroxybenzoic, caffeic, p-coumaric, ferulic, gallic, gen-tisic, protocatechuic, salicylic, sinapic, syringic... 

Figure 5. Relationship of depolarization of membrane electrical potential (E) in excised roots of barley 250 flM benzoic acids against their partition coefficients (log P). The numbers correspond to specific benzoic acid derivatives (1) salicylic, (2) -hydroxybenzoic, (3) protocatechuic, (4) gentisic,...

Kampa et al. made the interesting observation that protocatechuic acid, which is found in grapes and red wine from Vitis vimfera (Vitaceae), showed a time- and dose-dependent inhibitory effect on cell growth of T47D human breast cancer cells at low concentrations (108). The phenolic compound is a potent inhibitor of topoisomerase I (109). The plant likely contains some germanacrolides because these sesquiterpenes are known... 

Piperonylic acid has been made by the oxidation of piperic acid,1 piperonal,1 safrole2 and isosafrole2 with potassium permanganate. It has also been prepared by the action of methylene iodide on protocatechuic acid 3 in the presence of alkali. 

One last class of mononuclear non-haem iron enzyme that we have not yet considered, consists of the microbial superoxide dismutases with Fe(III) at their active site. The crystal structure of the E. coli enzyme shows a coordination geometry reminiscent of protocatechuate 3,4-dioxygenase, with four endogenous protein ligands, three His and one Asp residue, and one bound water molecule (Carlioz et ah, 1988). 

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