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PubMedDate not supplied

Variability in the enzyme properties of Pseudomonas aeruginosa strain 2x oxidizing p-xylene.

A culture of Pseudomonas aeruginosa 2x was observed for its spontaneous variability for growth on p-xylene and the intermediate products of its metabolism. The highest variability was found for ability to grow on p-xylene and pyrocatechol, and a variability an order of magnitude lower was found for ability to grow on protocatechuate and p-toluate. No variability was found for the character "ability to grow on p-hydroxybenzoate." The activity of the key enzymes for the oxidation of p-xylene was studied in p-xylene-negative strains. The difference between the p-xylene-positive wild type strain and the spontaneous p-xylene-negative strains was found to be linked to changes in the regulatory mechanisms for several enzymes: p-xylene methylhydroxylase and the enzymes involved in the breakdown of the aromatic ring. In addition, the appearance of p-xylene-negative strains was linked with a significant fall in the specific activity of all enzymes, except pyrocatechuase, which was replaced by metapyrocatechuase on a number of substrates.

4-Hydroxybenzoate-3-Monooxygenase↗

PubMedDate not supplied

Spectrophotometric investigations of the assay of physiologically active catecholamines in pharmaceutical formulations.

Two simple, sensitive, and accurate spectrophotometric methods are proposed for the determination of levodopa (LD), methyldopa (MD), dopamine hydrochloride (DP), and pyrocatechol (PC) in pure and pharmaceutical preparations. The methods are based on measurement of the absorbances of tris(o-phenanthroline)iron(II) (method A) and tris(bipyridyl)iron(II) (method B) obtained by the oxidation of the catecholamines by iron(III) in the presence of 1,10-phenanthroline and 2,2'-bipyridyl at 510 and 522 nm, respectively. The absorbances were found to increase linearly with increases in the concentrations of the catecholamines, results which were corroborated by the calculated correlation coefficients (0.9990-0.9996). Beer's law was valid over the concentration ranges of 0.04-0.6, 0.06-0.75, 0.06-0.65, and 0.05-0.70 microg/mL in method A and 0.02-1.0, 0.04-1.3, 0.05-1.0, and 0.06-1.1 microg/mL in method B for PC, MD, LD, and DP, respectively. The common excipients and additives did not interfere in their determinations. The proposed methods were successfully applied to the assay of LD, MD, and DP in various dosage forms. The results were validated by statistical analysis.

Catecholamines↗

PubMedDate not supplied

[Comparative study of the extracellular laccases from Cerrena unicolor 059 0784 and Pleurotus oastreatus 0432].

The laccases of the basidiomycetes Cerrena unicolor 059, C. unicolor 0784, and Pleurotus oastreatus 0432 were assayed comparatively. The laccases were isolated as homogenous preparations with molecular weight 55, 56, and 57 kD, respectively. The three enzymes were found to be glycoproteins. The carbohydrate moiety of the glycoproteins included mannose, galactose, and N-acetylglucosamine. The carbohydrate moiety of the laccases from C. unicolor 059, C. unicolor 0784, and P. oastreatus 0432 accounted for 17, 23, and 24%, respectively. The pH optimum of the enzymes was at 4.0, 3.75, and 5.6, respectively. Thermal stability testing of laccases at 40 degrees C revealed that the C. unicolor 0784 enzyme was characterized by the highest thermal stability (after 172-h incubation the enzyme activity was maintained at a level of 25%). The Michaelis constant (Km) values of the reactions of oxidation of pyrocatechol, hydroquinone, and potassium ferrocyanide catalyzed by the basidiomycete laccases were determined.

Basidiomycota↗

PubMed2004

[Dynamic changes of enzymes activities and growth factors contents in human colostrum].

OBJECTIVE: To study the dynamic changes of the activities of superoxide dismutase (SOD), amylase (AM) and alkaline phosphatase (ALP) and of the contents of epithelium growth factors (EGF) and insulin growth factors (IGF-1) in human colostrum (lactation 1 - 7 days postpartum). METHODS: A total of 118 samples of human colostrum were taken from 20 healthy women postpartum. The activities of SOD, AM and ALP in human colostrum were determined by methods of pyrogallol autoxidation, colorimetry of iodine-starch and pyrocatechol phosphate respectively. EGF and IGF-1 contents in human colostrum were measured by radioimmunoassay. RESULTS: The SOD activity of human colostrum increased slightly during lactation 1 - 4 days postpartum, from (18.7 +/- 2.2) kU/L to (22.5 +/- 2.9) kU/L, then it tended to decrease, being (11.2 +/- 2.1) kU/L on the 7th day. The SOD activities in lactation 1 - 5 days postpartum were significantly higher than that on day 7 (P < 0.05 or P < 0.01). AM and ALP activities of human colostrum gradually decreased within a week postpartum. AM activity declined from (155 +/- 12) kU/L to (17 +/- 4) kU/L. ALP activity declined from (105 +/- 17) kU/L to (54 +/- 9) kU/L. AM activities in lactation 1 - 5 days postpartum were significantly higher than that on day 7 (P < 0.05 or P < 0.01); and ALP activity on the first lactation day was significantly higher than that on day 7 (P < 0.05). EGF and IGF-1 concentrations in human colostrum quickly declined during lactation 1 - 4 days postpartum. EGF concentration decreased from (105 +/- 11) micro g/L to (40 +/- 5) micro g/L, and IGF-1 concentration decreased from (25.9 +/- 2.7) micro g/L to (5.6 +/- 1.3) micro g/L. Both concentrations altered slightly during lactation 4 - 7 days postpartum. EGF concentrations in lactation 1 - 3 days postpartum were remarkably higher than that on day 7 (P < 0.05 or P < 0.01); IGF-1 concentration on the first lactation day was significantly higher than that on day 7 (P < 0.01). CONCLUSIONS: Human colostrum contains SOD, AM and ALP with high activities, and is also rich in EGF and IGF-1. All of these are indispensable to normal growth and development of infants. Breast-feeding should be emphasized and encouraged for infants.

Adult↗

PubMed2006

In vitro antioxidant activity of Diospyros malabarica Kostel bark.

Antioxidant activity of defatted methanol extract of D. malabarica bark was studied for its free radical scavenging property on different in vitro models e.g. 1,1-diphenyl-2-picryl hydrazyl (DPPH), nitric oxide, superoxide, hydroxyl radical and lipid peroxide radical model. The extract showed good dose-dependent free radical scavenging property in all the models except in hydroxyl radical inhibition assay. IC50 values were found to be 9.16, 13.21, 25.27 and 17.33 microg/ml respectively in DPPH, nitric oxide, superoxide and lipid peroxidation inhibition assays. In hydroxyl radical inhibition assay 1000 microg/ml extract showed only 10% inhibition with respect to the control. Measurement of total phenolic compounds by Folin-Ciocalteu's phenol reagent indicated that 1 mg of the extract contained 120.7 microg equivalent of pyrocatechol. The results indicate that the antioxidant property of the extract may be due to the high content of phenolic compounds. However, the underlying mechanism may not involve hydroxyl radical scavenging property.

Animals↗

PubMedDate not supplied

[Consumption of water-insoluble phenolic products of lignin pyrolysis by the strain Penicillium tardum H-2].

Abstract-Physiological and biochemical properties of the strain Penicillium tardum H-2, a degrader of phenolic compounds formed during lignin pyrolysis, have been characterized. The micromycete P. tardum H-2 can consume phenol, pyrocatechol, p-cresol, vanillin, and guaiacum resin. When grown in a medium containing the water-soluble fraction of lignin pyrolysis waste at concentrations from 0.5 to 2%, it consumes 62-72% of the phenolic components of the waste. According to gas-liquid chromatography, cultivation of P. tardum H-2 in a medium with liquid pyrolysis products results in a complete consumption of the phenol-cresol fraction.

Benzaldehydes↗

PubMedDate not supplied

[Yellow laccase from the fungus Pleurotus ostreatus D1: purification and characterization].

Yellow laccase was isolated from a solid-phase culture of the fungus Pleurotus ostreatus D1 and characterized. It is a copper-containing enzyme with molecular weight 64 kDa. Its absorption spectrum lacks the maximum at 610 nm, characteristic of fungal laccases and corresponding to type I copper atom. The optimum pH values for the enzyme were determined. They proved to be: 7.0 for syringaldazine, 8.0 for pyrocatechol, and 4.0 for 2,2'-azine-bis-(3-ethylbenzothiazoline-6-sulfonate and 2,6-dimethoxyphenol. Kinetic parameters (Km and Vmax) for oxidation of these substrates were determined. The effect of inhibitors (SDS, 2-mercaptoethanol, and EDTA) on the activity of the enzyme was studied. It was shown that yellow laccase from Pleurotus ostreatus D1 oxidized anthracene to anthraquinone by 95% without any mediator.

Anthracenes↗

PubMedDate not supplied

[Catalysis of the biodegradation of unusable medicines by alkanotrophic rhodococci].

Experiments on the biodegradation of unusable medicines containing a phenolic hydroxy group by actinobacteria of the genus Rhodococcus were performed. Six species and sixty-four strains were tested. It was found that rhodococci could degrade paracetamol, and some R. ruber strains showed high levels of its degradation. An efficient method for the identification and quantification of paracetamol and the products of its conversion (p-aminophenol, pyrocatechol, and hydroquinone) immediately in the culture liquid was developed. Conditions for the complete biodegradation of paracetamol dosage forms (pills) were optimized. The experimental results can be applied for the development of biotechnological methods for degrading medicines: faked, rejected, or those that are expired.

Acetaminophen↗

PubMed1978

(+/-)-[3H]Epinephrine and (-)[3H]dihydroalprenolol binding to beta1- and beta2-noradrenergic receptors in brain, heart, and lung membranes.

(+/-)-[3H]Epinephrine binds to beta-receptors in calf cerebellar and rat lung membranes in the presence of 1.0 mM pyrocatechol and 1.0 microM phentolamine, with dissociation constants at 4 degrees C of 11 nM and 24 nM, respectively. (+/-)-[3H]Epinephrine associates to equilibrium within 20 min in both tissues, and over 50% of the binding is rapidly dissociable. Inhibition of binding by agonists and antagonists is highly stereoselective, and the structure-activity relationships of adrenergic agents in inhibiting (+/-)-[3H]epinephrine binding suggest an interaction with beta2 type noradrenergic receptors. (-)-Isoproterenol has an apparent Ki of 2 nM, (-)-epinephrine is 1.5 to 3 times weaker, and (-)-norepinephrine is 30 to 60 times weaker. Salbutamol and terbutaline, selective beta2-agonists, are potent inhibitors of binding, as are several nonspecific antagonists. Properties of the sites labeled by (+/-)-[3H]epinephrine in calf cerebellum and rat lung are closely similar. (-)-[3H]Dihydroalprenolol binding in calf cerebellum and rat lung also shows beta2 characteristics. Antagonists have similar potencies in inhibiting (-)-[3H]dihydroalprenolol and (+/-)-[3H]epinephrine binding in both tissues, but agonists are in general more potent inhibitors of (+/-)-[3H]epinephrine. Sodium and lithium selectively lower the affinity of (+/-)-[3H]epinephrine at its binding sites and the affinities of agonists, but not antagonists, at the (-)-[3H]dihydroalprenolol site. Specific (+/-)-[3H]epinephrine binding was not detectable in calf cortex and rat heart, where (-)-[3H]dihydroalprenolol binding suggests a beta1-receptor. A physiological significance of (+/-)-[3H]epinephrine binding is suggested by the strong correlation for agonists and antagonists between affinities in inhibiting binding, and in stimulating or inhibiting a beta-receptor-coupled adenylate cyclase in frog erythrocytes.

Alprenolol↗

PubMed1977

Response of the atrial pacemaker to dobutamine.

The action of dobutamine, (+/-)-4- [2- [[3-(p-hydroxyphenyl)-1-methylpropyl]amino]ethyl] pyrocatechol hydrochloride was studied on the pacemaker of the isolated rat atria. The dose-chronotropic response curve showed a typical bell-dome shape of the sympathomimetic amines. Reserpinization of the animals did not change the curve of the agonist. Cocaine (6.7 microgram/ml) induced a decrease of the sensitivity of the rat atria pacemaker for dobutamine (p less than 0.001). Propranolol (3 X 10(-8) and 10(-7) M) provoked a shift to the right of the dose-response curve for dobutamine. Also, the last concentration of the antagonist depressed the maxima (p less than 0.01). Phentolamine failed to prove a possible alpha-adrenergic action of the drug on the pacemaker. The response to dobutamine was not affected when monoaminoxidase was inhibited by pretreatment with pargyline, or when catechol-O-methyltransferase was inhibited by exposure to U-0521 (3,4 dihydroxy-alpha-methylpropiophenone). These results indicate that dobutamine: a) is a beta-adrenergic agent, b) is not a good substrate of MAO, c) is a direct-acting sympathomimetic amine.

Adrenergic beta-Antagonists↗

PubMedDate not supplied

[Determination of 3,4-dioxyphenyl-L-alanine by spectrophotometric and chromatographic methods in enzymatic synthesis using microbial cells].

A possibility of using the ninhydrin reaction for 3,4-dihydroxyphenyl-L-alanine (DOPA) determining during the synthesis from pyrocatechol and ammonium pyruvate was verified by using free and immobilized cells of Citrobacter freundii, st. 62. Spectrophotometric assay was performed at the adsorption maximum for the DOPA-ninhydrin complex at 390 nm. DOPA can be reliably quantified in the presence of all components at 20-fold and greater dilution of the reaction mixture. A high-sensitive quantitative assay of the reaction mixture was developed based on phase-reversed HPLC. A quantitative correlation was observed between spectrophotometric and chromatographic assays. The assays were employed to study in detail the initial period and equilibrium of DOPA synthesis and its characteristic features, which made it possible to construct a kinetic model of the process.

Catechols↗

PubMedDate not supplied

[The effect of alloxan on activity of various enzymes of phosphorus metabolism in vitro].

Effect of alloxan on activity of acetylphosphatase, alkaline and acid phosphatases, phenylpyrophosphatase was studied in vitro. Alloxan at concentrations 100 microM-10 mM inhibited acid phosphatase and especially alkaline phosphatase. Reducing agents (pyrocatechol, hydroquinone, ascorbic acid), which are easily converted into corresponding oxidized forms, at concentrations 100 microM-1.0 mM activated alkaline phosphatase in rat kidney and small intestine.

Acid Phosphatase↗

PubMed1987

The electron spin resonance study on primary photochemical reaction of hematoporphyrin derivative.

The rate of oxygen consumption and the yield of free radical anion of hematoporphyrin derivative (HPD) in aqueous solutions of HPD and pyrocatechol were measured by the probe 2,2,6,6-tetramethyl-4-piperidone-1-oxyl. It has been found that both singlet oxygen and free radical mechanisms exist simultaneously in primary photochemical reactions, and there is a competition between both mechanisms. When the oxygen concentration in solutions comes down to 12-14% of the stanting level, the predominant mechanism can be changed from the singlet oxygen to the free radical. Whether HPD exists in aggregation state is very important to photosensitization mechanisms. In the presence of the aggregation state of HPD, the predominant mechanism is the free radical, and photosensitization effects of HPD are all the better.

Catechols↗

PubMed1985

Effect of reductones on cyclic 3', 5'-adenosine monophosphate phosphodiesterase.

The effect of some reductones such as ascorbic acid (AsA), triose reductone (TR), epinephrine (Ep) and their derivatives on cyclic 3', 5'-adenosine monophosphate phosphodiesterase (cAMP PDE) was studied in the presence or absence of Cu2+. AsA, TR, Ep and the reductones related to them inhibited cAMP PDE activity. Among the reductones, TR showed the highest inhibition. AsA, 5-methyl-3,4-dihydroxytetrone, pyrocatechol, p-hydroxyquinone and resorcinol had a relatively high inhibiting activity. The type of inhibition of AsA, TR and Ep was uncompetitive, competitive and noncompetitive, respectively. Cu2+ enhanced the inhibitory action of the reductones markedly and altered the type of inhibition of the reductones.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1986

Relationship between structure and activity of aspirin-related compounds on the inhibition of in vitro platelet aggregation.

Thirteen aspirin-related compounds were tested for inhibitory activity on platelet aggregation in human platelet rich plasma (PRP) induced with ADP, collagen and arachidonic acid. The following structure-activity relationships were found: none of the functional groups used to replace the acetyl group retained the significant antiaggregant activity of aspirin; anti-aggregant activity was enhanced when the carboxylic group was replaced with a hydroxyl or an acetylated hydroxyl group. The activity of these mono and diacetylated pyrocatechol derivatives was unaffected by incubation of PRP with sodium salicylate.

Adenosine Diphosphate↗

PubMed1986

[Benzoxazolinone phenylethanolamine antagonists of adrenergic receptors. A chemical and pharmacodynamic study].

Benzoxazolinone can be considered as a bioisosteric analogue of pyrocatechol. This concept has led to the synthesis of benzoxazolinonic phenylethanolamines. The pharmacological study shows that these compounds possess an affinity for adrenergic receptors. Compound (XXXIV), the most interesting, is a competitive alpha and beta adrenergic antagonist which has been studied for antihypertensive activity.

Animals↗

PubMedDate not supplied

[Synthesis of tyrosine and 3,4-dihydroxyphenylalanine by bacteria Citrobacter freundii].

Among facultative-anaerobic bacteria utilizing formic acid, a large number of strains having tyrosine phenol lyase were found. The enzyme can catalyze synthesis of tyrosine and 3,4-dihydroxy phenyl alanine (DOPA) from pyruvate, ammonium and, accordingly, phenol and pyrocatechol. These strains were identified as Citrobacter freundii. Cell suspensions of the most active strains synthesized up to 75 g/l tyrosine for 12 hr, up to 86 g/l tyrosine for 24 hr, and up to 29 g/l DOPA for 42 hr. A medium containing yeast autolysate grown on hydrocarbons can be recommended to produce cells having a high tyrosine phenol lyase activity.

Ammonia↗

PubMed1978

Effects of dobutamine on coronary circulation and cardiac metabolism of the dog.

Effects of (+/-)-4-[2-(3-p-hydroxyphenyl-1-methyl-amino)ethyl]pyrocatechol (dobutamine) on coronary circulation and cardiac metabolism were investigated using the heart in vivo and the isolated perfused heart of dogs. In the heart in vivo dobutamine 1--30 microgram/kg i.v. and 1--100 microgram i.c. produced dose-dependent increases in coronary perfusion pressure, coronary blood flow, heart rate and left intraventricular pressure. In the perfused heart dobutamine 10 microgram i.c. increased coronary flow, heart rate, cardiac contractility and myocardial oxygen consumption. Delta redox potentials decreased but did not show negative values. Propranolol 0.1 mg/kg i.v. and 0.1 mg i.c. inhibited these effects of dobutamine. Dobutamine shows basically the same actions as isoproterenol, but does not reduce the coronary perfusion pressure by the relatively high dose applied. The results suggest that dobutamine may have a selective adrenergic beta 1 receptor stimulating action on the heart and have a merit in maintaining the coronary perfusion pressure.

Animals↗