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PubMed1990

Preservatives in insulin preparations impair leukocyte function. In vitro study.

m-Cresol and methyl p-hydroxybenzoate are preservatives in insulin preparations. As previously reported, in diabetic patients on continuous subcutaneous insulin infusion, users of insulin-containing m-cresol had significantly more inflamed infusion sites than users of insulin with methyl p-hydroxybenzoate. This study assessed the influence of insulin with and without these preservatives on leukocyte function. Leukocyte function was investigated in a killing experiment, expressed as the percentage of bacteria killed after 60 min incubation of bacteria (Staphylococcus aureus), polymorphonuclear leukocytes, serum, and insulin preparations. Because preservative is retained by the infusion device, insulin with preservative was tested before and after 1 and 4 days perfusion with a PVC pump catheter. After perfusion, the amount of preservative was reduced (percentage of original concentration after 1 and 4 days 8 and 30% m-cresol and 42 and 72% methyl p-hydroxybenzoate, respectively). The killing percentage in insulin with m-cresol reduced compared with insulin without preservative (mean +/- SE 95.4 +/- 0.8%) and the control without insulin (95.8 +/- 0.8%), both before and after 1 and 4 days perfusion (74.8 +/- 0.7, 80.2 +/- 2.8, and 80.6 +/- 1.6%, respectively; P less than 0.01). The same occurred in insulin with methyl p-hydroxybenzoate (85.0 +/- 0.9% before and 88.4 +/- 0.9 and 86.2 +/- 0.8% after 1 and 4 days perfusion; P less than 0.05). All insulin preparations with m-cresol caused lower killing percentages than corresponding insulin preparations with methyl p-hydroxybenzoate (P less than 0.05). These results demonstrate that both preservatives impaired leukocyte function, but m-cresol was the most noxious in this respect.(ABSTRACT TRUNCATED AT 250 WORDS)

Cresols↗
PubMed1993

Evaluation of phototoxic properties of some food additives: sulfites exhibit prominent phototoxicity.

Additives are used widely to enhance the quality of food products. To identify possible phototoxic properties, 13 food additives (benzoic acid, sodium benzoate, 4-hydroxybenzoic acid, 4-hydroxybenzoic acid methyl ester, 4-hydroxybenzoic ethyl ester, 4-hydroxybenzoic acid propyl ester, p-hydroxybenzoic acid n-butyl ester, benzyl alcohol, sorbic acid, potassium sorbate, propionic acid, sodium disulfite and sodium sulfite) were evaluated in vitro by means of a photohemolysis test using suspensions of human erythrocytes. Irradiation was performed with various light sources differing with regard to their spectral irradiance. Sodium sulfite and sodium disulfite induced photohemolysis up to almost 100%, the effect depending on the concentration of the compounds and UV dose administered. Radiation rich in UVB was most effective; a sunlight-simulating lamp induced photohemolysis to a lesser degree. All other substances tested did not cause significant photohemolysis. As sulfites are frequently encountered, they may contribute to UVB sensitivity. The clinical significance of these findings has to be established by further work.

Dermatitis, Phototoxic↗
PubMed1976

On the solubilization properties of surfactant-polymer complexes.

Polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) affect the solubilization properties of sodium dodecyl sulphate (SDS). When these polymers are added to SDS solution, its solubilization power for riboflavin, khellin and propyl p-hydroxybenzoate is markedly decreased. In case of riboflavin and khellin, the polymer effect is more pronounced at high surfactant concentrations; for propyl p-hydroxybenzoate, the polymer effect is inversely proportional to the surfactant concentration. On the other hand, the solubilization power of SDS towards methyl and butyl p-hydroxybenzoate is greatly enhanced by PEG or PVP. In case of methyl p-hydroxybenzoate the effect of PEG is more pronounced at high surfactant concentrations; the effect of PVP is not significantly dependent on the surfactant concentration. For butyl p-hydroxybenzoate, the polymer effect decreases markedly with increasing surfactant concentration.

Khellin↗
PubMed1975

Kinetic analysis of the metabolism of benzo(a)pyrene to phenols, dihydrodiols, and quinones by high-pressure chromatography compared to analysis by aryl hydrocarbon hydroxylase assay, and the effect of enzyme induction.

High-pressure liquid chromatography was used to analyze the rate of benzo(a)pyrene metabolite formation by liver microsomes from control and 3-methylcholanthrene-treated rats. The relative amounts of each metabolite formed were determined with several concentrations of microsomal mixed-function oxidases. The specific activity, i.e., amount formed per mg protein per min, was found to be constant for the formation of 3-hydroxybenzo(a)pyrene and 4,5-dihydro-4,5-dihydroxybenzo(a)pyrene. The specific activity for the formation of 9,10-dihydro-9,10-dihydroxybenzo(a)pyrene was higher at high microsomal enzyme concentration. The formation of 9-hydroxybenzo(a)pyrene, however, did not increase with greater amounts of microsomes. The data indicate that 9-hydroxybenzo(a)pyrene is a nonenzymatic product derived from a reactive intermediate, probably benzo(a)pyrene-9,10-oxide. The relatively constant specific activity for the formation of 4,5-dihydro-4,5-dihydroxybenzo(a)pyrene with several enzyme concentrations suggests that the K-region epoxide, benzo(a)pyrene-4,5-oxide, is the most stable of the benzo(a)pyrene epoxide intermediates. The relative percentages of each metabolite fraction found are as follows: 3-hydroxybenzo(a)pyrene, 36; 9-hydroxybenzo(a)pyrene, 3 to 13; 9,10-dihydro-9,10-dihydroxybenzo(a)pyrene, 15 to 25; 4,5-dihydro-4,5-dihydroxybenzo(a)pyrene, 8; 7,8-dihydro-7,8-dihydroxybenzo(a)pyrene, 12 to 14; benzo(a)pyrene quinones, 14 to 17. Induction of the enzyme system by 3-methylcholanthrene increases the amount of each metabolite formed to a different extent. The amount of 9,10-dihydro-9,10-dihydroxy- and 7,8-dihydro-7,8-dihydroxybenzo(a)pyrene formed are markedly increased relative to the increase in the other metabolites. Thus the induction of the enzyme may specifically alter pathways of metabolism relevant to carcinogenesis. This study also makes a detailed comparison between the results obtained by high-pressure liquid chromatography analysis and the standard aryl hydrocarbon hydroxylase assay and further develops the chromatographic analysis of benzo(a)pyrene metabolites.

Animals↗
PubMed1984

Interaction between bacterial metabolites and some pesticides. II. Change of phytotoxicity of the herbicide Roneet by the phenolic metabolites of Arthrobacter sp.

The bacteria from Arthrobacter genus isolated from sugar beet rhizosphere were found to produce gallic, protocatechuic, p-hydroxybenzoic, syryngic, vanillic, veratric acids, p-quinone and two unidentified phenolic compounds. The mixture of the bacterial phenolic compounds increased the phytotoxicity of Roneet, inhibiting the germination of wheat. Model experiments showed that the phenolic acids used with the herbicide Roneet increased its phytotoxicity and p-hydroxybenzoic acid was found to be the most active. It was found that in the presence of the phenolic acids, particularly of p-hydroxybenzoic acid, the herbicide content in the seeds of wheat was reduced. The UV and IR spectra of equimolar amounts of p-hydroxybenzoic acid and Roneet showed the hydrogen bond between H of carboxylic group of acid and O of C=O group of the Roneet molecule. It could be concluded that Roneet conjugated with p-hydroxybenzoic acid was more phytotoxic than the initial compounds.

Arthrobacter↗
PubMed1994

Utilization of some phenolic compounds by Azotobacter chroococcum and their effect on growth and nitrogenase activity.

Azotobacter chroococcum MH1 was grown in a mannitol and nitrogen free medium supplemented with p-hydroxybenzoic acid, resorcinol, catechol or vanillic acid as a sole carbon source. Growth and nitrogenase activity of p-hydroxybenzoic acid were supported by 8, 6 and 4 mM of p-hydroxybenzoic acid, resorcinol and catechol, respectively. The generation time of 1.71 h in p-hydroxybenzoic acid did not differ from a generation time of 1.64 h, when grown in mannitol. The compound p-hydroxybenzoic acid was utilized rapidly. However, the decomposition of other phenolic compounds tested proceeded slowly. These results suggested that phenolic compounds released during biodegradation of plant wastes could be utilized as carbon sources for both growth and nitrogen fixation of Azotobacter chroococcum.

Azotobacter↗
PubMed1976

Mutagenicity and cytotoxicity of benzo(a)pyrene arene oxides, phenols, quinones, and dihydrodiols in bacterial and mammalian cells.

Twenty-nine benzo(a)pyrene derivatives were tested for mutagenic acitivity without metabolic activation in Salmonella typhimurium strains TA98, TA100, and TA1538 and in Chinese hamster V79 cells. The compounds studied included 4 arene oxides, all 12 isomeric phenols, 5 quinones, and 8 dihydrodiols. Benzo(a)pyrene 4,5-oxide was the most mutagenic of the compounds tested in both the bacterial and mammalian systems. The other arene oxides [benzo(a)pyrene 7,8-, 9,10-, and 11,12-oxides] were only weakly mutagenic in the S. typhimurium strains. However, in Chinese hamster V79 cells benzo(a)pyrene 11,12-oxide. Among the phenols, 6-hydroxybenzo(a)pyrene and 12-hydroxybenzo(a)pyrene were moderately mutagenic in strain TA98 of S. typhimurium, and 6-hydroxybenzo(a)pyrene was moderately mutagenic in V79 cells. The other 10 phenols, 5 quinones [benzo(a)pyrene 1,6-, 3,6-, 4,5-, 6, 12-, and 11,12-quinones] and 8 dihydrodiols [benzo(a)pyrene cis-4,5,trans-4,5-, cis-7,8-, trans-7,8-, cis-9,10-, trans-9,10-, cis-11,12-, and trans-11, 12-dihydrodiols] were eitherinactive or only weekly mutagenic. 1-Hydroxybenzo(a)pyrene and 3-hydroxybenzo(a)pyrene were weakly mutagenic in strain TA98 of S. typhimurium, and benzo(a)pyrene 7,8-dihydrodiol was weakly mutagenic in V79 cells. Benzo(a)pyrene 11,12-quinone was extremely cytotoxic to the V79 cells but had no observable toxicity in the bacterial strains.

Animals↗
PubMed2006

Relationship between chlorine consumption and chlorination by-products formation for model compounds.

The objective of this research is to investigate the relationship between chlorine decay and the formations of disinfection by-products (DBP), including trichloromethane (TCM) and chloroacetic acid (CAA) in the presence of four model compounds, i.e., resorcinol, phloroglucinol, p-hydroxybenzoic acid, and m-hydroxybenzoic acid. The chlorine degradation in model compounds with OH and/or COOH functional groups were rapid after chlorination. The TCM yields of carboxylic group substituted compounds (3-hydroxybenzoic acid [3-HBA], 4-hydroxybenzoic acid [4-HBA]) were found to be lower than that of the m-dihydroxy substituted compounds. Phloroglucinol, with one more OH substitution group than resorcinol, tends to form significant amounts of CAA after chlorination. However, it was observed that with the COOH substitution of 3-HBA and 4-HBA tend to exhibit more CAA formation potential than resorcinol. The developed parallel second and first-order reaction model for chlorine demand has been successfully utilized for TCM, CAA and DBP formation modeling. A high correlation between CAA and TCM was observed for the model compounds.

Acetates↗
PubMed1983

Rate assay for determination of serum pseudo-cholinesterase activity.

A simple and reproducible method for the determination of serum pseudo-cholinesterase activity was developed by making use of a stable substrate, p-hydroxybenzoylcholine, with p-hydroxybenzoate hydroxylase as a linked enzyme. The method is based on spectrophotometric measurement of the decrease of NADPH. p-Hydroxybenzoate released from p-hydroxybenzoylcholine is hydroxylated by the action of p-hydroxybenzoate hydroxylase in the presence of NADPH and O2 to produce 3,4-dihydroxybenzoate and NADP+. This method is superior to the conventional methods in that this substrate is extremely stable up to pH 9.0, which is close to the optimum pH for the assay (pH 8.0). Serum interference was resolved by the use of p-hydroxybenzoate hydroxylase as a linked enzyme. The Km value of pseudocholinesterase for p-hydroxybenzoylcholine is 1 X 10(-5) M. The results of our method and Garry's method (Clin. Chem. 11, 91-96, 1965) correlated well (r = 0.962). The within-run and between-run C.V. values were 2.1 and 2.7, respectively.

4-Hydroxybenzoate-3-Monooxygenase↗
PubMed1990

Catabolism of benzoate and monohydroxylated benzoates by Amycolatopsis and Streptomyces spp.

Eight actinomycetes of the genera Amycolatopsis and Streptomyces were tested for the degradation of aromatic compounds by growth in a liquid medium containing benzoate, monohydroxylated benzoates, or quinate as the principal carbon source. Benzoate was converted to catechol. The key intermediate in the degradation of salicylate was either catechol or gentisate, while m-hydroxybenzoate was metabolized via gentisate or protocatechuate. p-Hydroxybenzoate and quinate were converted to protocatechuate. Catechol, gentisate, and protocatechuate were cleaved by catechol 1,2-dioxygenase, gentisate 1,2-dioxygenase, and protocatechuate 3,4-dioxygenase, respectively. The requirement for glutathione in the gentisate pathway was dependent on the substrate and the particular strain. The conversion of p-hydroxybenzoate to protocatechuate by p-hydroxybenzoate hydroxylase was gratuitously induced by all substrates that were metabolized via protocatechuate as an intermediate, while protocatechuate 3,4-dioxygenase was gratuitously induced by benzoate and salicylate in two Amycolatopsis strains.

Actinomycetales↗
PubMed2004

Proteome analysis of Pseudomonas sp. K82 biodegradation pathways.

Pseudomonas sp. K82 is a soil bacterium that can degrade and use monocyclic aromatic compounds including aniline, 3-methylaniline, 4-methylaniline, benzoate and p-hydroxybenzoate as its sole carbon and energy sources. In order to understand the impact of these aromatic compounds on metabolic pathways in Pseudomonas sp. K82, proteomes obtained from cultures exposed to different substrates were displayed by two-dimensional gel electrophoresis and were compared to search for differentially induced metabolic enzymes. Column separations of active fractions were performed to identify major biodegradation enzymes. More than thirty proteins involved in biodegradation and other types of metabolism were identified by electrospray ionization-quadrupole time of flight mass spectrometry. The proteome analysis suggested that Pseudomonas sp. K82 has three main metabolic pathways to degrade these aromatic compounds and induces specific metabolic pathways for each compound. The catechol 2,3-dioxygenase (CD2,3) pathway was the major pathway and the catechol 1,2-dioxygenase (beta-ketoadipate) pathway was the secondary pathway induced by aniline (aniline analogues) exposure. On the other hand, the catechol 1,2-dioxygenase pathway was the major pathway induced by benzoate exposure. For the degradation of p-hydroxybenzoate, the protocatechuate 4,5-dioxygenase pathway was the major degradation pathway induced. The nuclear magnetic resonance analysis of substrates demonstrated that Pseudomonas sp. K82 metabolizes some aromatic compounds more rapidly than others (benzoate > p-hydroxybenzoate > aniline) and that when combined, p-hydroxybenzoate metabolism is repressed by the presence of benzoate or aniline. These results suggest that proteome analysis can be useful in the high throughput study of bacterial metabolic pathways, including that of biodegradation, and that inter-relationships exist with respect to the metabolic pathways of aromatic compounds in Pseudomonas sp. K82.

Aniline Compounds↗
PubMed2000

Adsorption and Chemical Modification of Phenols on a Silver Surface.

The adsorption of phenols of different natures on silver colloidal particles is studied here by surface-enhanced Raman spectroscopy (SERS). The studied compounds can be classified in three groups: (a) cinnamic acic derivatives: caffeic and isoferulic acids; (b) catechol; and (c) the phenols derived from benzoic acid: m- and p-hydroxybenzoic acids and salicylic, vanillic, and gallic acids. The interest of these compounds lies in the fact that they are naturally occurring molecules with significant importance in relation to plant metabolism, soil chemistry, and vegetal food stability. In addition, many of these compounds have antioxidant properties derived from their high affinity toward atmospheric oxygen. They exhibit high reactivity that may be enhanced in the presence of a metal surface such as those employed for SERS spectroscopy. From the SERS results it can be deduced that a clear chemical change of caffeic and gallic acid and catechol occurred. The chemical modification consists mainly of polymerization connected to existence in the molecule of o-diphenol moieties. In the case of m-hydroxybenzoic acid the chemical change may occur at low pH at which a reorientation of the molecule on the surface takes place, while in the o-hydroxybenzoic acid the only chemical change seems to be the internal H bond breakdown induced by the complexation with the metal. Finally, isoferulic and p-hydroxybenzoic acids do not show any chemical modification upon adsorption on the metal, which takes place through the carboxylate group adopting the molecule a standing up orientation. The case of vanillic acid is not so clear, although possible chemical modification is also possible for this adsorbate. From the results found in this work it can be inferred that the factors influencing possible chemical modification are the chemical structure of the adsorbate and its orientation and interaction with the surface. Copyright 2000 Academic Press.

Journal Article↗
PubMed1975

Studies on tocopherol derivatives: V. Intestinal absorption of several d,1-3,4-3H2-alpha-tocopheryl esters in the rat.

Twelve d,1-3,4-3H2-alpha-tocopheryl esters were synthesized from d,1-3,4-3H2-alpha-tocopherol. They were acetate, propionate, butyrate, isobutyrate, caprylate, palmitate, acid succinate, benzoate, nicotinate, o-hydroxybenzoate, o-acetoxybenzoate, and pivalate. The hydrolysis of these esters with bile-pancreatic juice and with 9,000 x g supernatant of small intestine and liver homogenates of rats was examined. When these esters were incubated in small intestine or liver supernatants, hydrolysis occurred at a similar rate. In the incubation experiments, alpha-tocopheryl acetate, propionate, butyrate, isobutyrate, caprylate, palmitate, and acid succinate were classified as an easily hydrolyzable group. Alpha-tocopheryl benzoate and nicotinate were in a moderately hydrolyzable group. O-hydroxybenzoate and pivalate, which resisted hydrolysis, were in a scarcely hydrolyzable group. O-acetoxybenzoate was easily hydrolyzed to the o-hydroxybenzoate. Hydrolysis on straight chain fatty acid esters of alpha-tocopherol easily occurred in bile-pancreatic juice. In in vivo experiments, the lymphatic absorption rate of 6 esters, acetate, palmitate, acid succinate, nicotinate, o-hydroxybenzoate, and pivalate, was measured on thoracic duct fistula rats. Easily hydrolyzable esters were recovered mostly in lymph as alpha-tocopherol, whereas, an ester which strongly resisted hydrolysis, such as pivalate, appeared mainly unchanged. This fact suggested that hydrolysis of alpha-tocopheryl esters was not necessarily a prerequisite for intestinal absorption. The percentage of absorption of slowly hydrolyzed esters in lymph was relatively lower than that of moderately or easily hydrolyzable esters.

Animals↗
PubMed2006

Pelotomaculum terephthalicum sp. nov. and Pelotomaculum isophthalicum sp. nov.: two anaerobic bacteria that degrade phthalate isomers in syntrophic association with hydrogenotrophic methanogens.

An anaerobic phthalate isomer-degrading strain (JT(T)) that we previously isolated was characterized. In addition, a strictly anaerobic, mesophilic, syntrophic phthalate isomer-degrading bacterium, designated strain JI(T), was isolated and characterized in this study. Both were non-motile rods that formed spores. In both strains, the optimal growth was observed at temperatures around 37 degrees C and neutral pH. In syntrophic co-culture with the hydrogenotrophic methanogen Methanospirillum hungatei, both strains could utilize two or three phthalate isomers for growth, and produce acetate and methane as end products. Strain JT(T) was able to grow on isophthalate, terephthalate, and a number of low-molecular weight aromatic compounds, such as benzoate, hydroquinone, 2-hydroxybenzoate, 3-hydroxybenzoate, 2,5-dihydroxybenzoate, 3-phenylpropionate in co-culture with M. hungatei. It could also grow on crotonate, hydroquinone and 2,5-dihydroxybenzoate in pure culture. Strain JI(T) utilized all of the three phthalate isomers as well as benzoate and 3-hydroxybenzoate for growth in co-culture with M. hungatei. No substrates were, however, found to support the axenic growth of strain JI(T). Neither strain JT(T) nor strain JI(T) could utilize sulfate, sulfite, thiosulfate, nitrate, fumarate, Fe (III) or 4-hydroxybenzoate as electron acceptor. Phylogenetically, strains JT(T) and JI(T) were relatively close to the members of the genera Pelotomaculum and Cryptanaerobacter in 'Desulfotomaculum lineage I'. Physiological and chemotaxonomic characteristics indicated that the two isolates should be classified into the genus Pelotomaculum, creating two novel species for them. Here, we propose Pelotomaculum terephthalicum sp. nov. and Pelotomaculum isophthalicum sp. nov. for strain JT(T) and strain JI(T), respectively. The type strains are strains JT(T) (= DSM 16121(T )= JCM 11824(T )= NBRC 100523(T)) and JI(T) (= JCM 12282(T) = BAA-1053(T)) for P. terephthalicum and P. isophthalicum, respectively.

Anaerobiosis↗
PubMed1981

The effects of modulation of microsomal epoxide hydrolase activity on microsome-catalyzed activation of benzo[alpha]pyrene and its covalent binding to DNA.

The effects of modulation of microsomal epoxide hydrolase activity on the binding of calf thymus DNA of benzo[alpha]pyrene metabolically activated by rat liver microsomes were investigated. In systems where microsomal epoxide hydrolase levels were not manipulated, 2 major bound species, one derived from 9-hydroxybenzo[alpha]pyrene and the other derived from benzo[alpha]pyrene 7,8-dihydrodiol, were found in approximately equivalent amounts. When epoxide hydrolase levels were increased, either by addition in vitro of purified enzyme or by induction in vivo by trans-stilbene oxide, the binding of the benzo[alpha]pyrene 7,8-dihydrodiol product was increased, while the binding of the 9-hydroxybenzo[alpha]pyrene product was practically eliminated. When microsomal epoxide hydrolase activity was decreased by selective inhibition with low concentrations of 1,1,1-trichloropropene 2,3-oxide, the binding of the species derived from 9-hydroxybenzo[alpha]pyrene was increased several-fold, while that of the species derived from benzo[alpha]pyrene 7,8-dihydrodiol was greatly decreased. The results indicate that the binding species derived from 9-hydroxybenzo[alpha]pyrene is formed through a metabolic pathway leading to an epoxide which is a substrate of microsomal epoxide hydrolase and that microsomal epoxide hydrolase is important in regulating the pattern of binding of individual microsomally-formed benzo[alpha]pyrene metabolites to DNA.

Animals↗
PubMed2002

Nonlinear analysis of dynamic binding in affinity capillary electrophoresis demonstrated for inclusion complexes of beta-cyclodextrin.

The stability of the molecular host-guest inclusion complexes of beta-cyclodextrin with benzoate and four different hydroxybenzoates is investigated. For the measurement of the binding constants an experimental method is devised that is based on affinity capillary electrophoresis (ACE) with indirect UV absorbance detection. We derive an explicit equation for effective mobilities in ACE experiments without violation of rigorous mass balance. This equation is employed in the nonlinear least-squares analyses of the experimental data yielding binding constants of 48+/-2 M(-1) for benzoate, 299+/-38 M(-1) for 2-hydroxybenzoate, 37+/-1 M(-1) for 3-hydroxybenzoate, 228+/-9 M(-1) for 4-hydroxybenzoate, and 895+/-110 M(-1) in the case of 2,4-dihydroxybenzoate.

Cyclodextrins↗
PubMed2001

Characterization of sago palm (Metroxylon sagu) lignin by analytical pyrolysis.

Dioxane lignin prepared from sago palm (Metroxylon sagu) was characterized by analytical pyrolysis coupled to gas chromatography-mass spectrometry. Large abundances of the p-hydroxybenzoates ester-linked to the lignin were proven by analytical pyrolysis as well as by mild alkaline treatment that produced p-hydroxybenzoic acid in 16.3% yield. Pyrolysis in the presence of tetramethylammonium hydroxide (TMAH) before and after alkaline treatment also showed the presence of ester- and ether-linked p-hydroxybenzoates. Quantitative results of pyrolysis showed that the sago palm lignin is of syringyl type. The relative abundances of TMAH/pyrolysis products derived from the syringyl beta-aryl ether substructures were 4.9 times those of the guaiacyl equivalents. Proton nuclear magnetic resonance analysis also showed the presence of the p-hydroxybenzoates and the predominance of the syringyl moiety over the guaiacyl ones in the sago palm lignin.

Gas Chromatography-Mass Spectrometry↗
PubMed1971

Ubiquinone biosynthesis in Escherichia coli K-12. Accumulation of an octaprenol, farnesylfarnesylgeraniol, by a multiple aromatic auxotroph.

Cell extracts of a multiple aromatic auxotroph of Escherichia coli K-12, strain AB2830, grown in the absence of precursors of the quinone rings of the ubiquinone and menaquinone molecules, converted 4-hydroxy[U-(14)C]benzoate into a mixture of 3-octaprenyl-4-hydroxybenzoate and 2-octaprenylphenol. An octaprenol, farnesylfarnesylgeraniol, was isolated from such cell extracts and characterized by n.m.r. and mass spectroscopy. Neither the octaprenol, nor polyprenylation of 4-hydroxy[U-(14)C]benzoate, could be detected in cell extracts of strain AB2830 grown in the presence of 0.1mm-4-hydroxybenzoate. It was concluded that, in the biosynthesis of ubiquinone, the polyprenyl side chain is added to 4-hydroxybenzoate as a C(40) unit, the active form of which is converted by cell extracts into farnesylfarnesylgeraniol. The multiple aromatic auxotroph, when grown in the absence of 4-hydroxybenzoate but in the presence of 4-aminobenzoate, converted the latter compound into 3-octaprenyl-4-aminobenzoate. This compound was isolated from whole cells and characterized by n.m.r. and mass spectroscopy.

Alcohols↗