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At least 397 records · Page 22Linked to original sources
PubMed2005

Importance of 3-hydroxy fatty acid composition of lipopeptides for biosurfactant activity.

Biosurfactant production may be an economic approach to improving oil recovery. To obtain candidates most suitable for oil recovery, 207 strains, mostly belonging to the genus Bacillus, were tested for growth and biosurfactant production in medium with 5% NaCl under aerobic and anaerobic conditions. All strains grew aerobically with 5% NaCl, and 147 strains produced a biosurfactant. Thirty-five strains grew anaerobically with 5% NaCl, and two produced a biosurfactant. In order to relate structural differences to activity, eight lipopeptide biosurfactants with different specific activities produced by various Bacillus species were purified by a new protocol. The amino acid compositions of the eight lipopeptides were the same (Glu/Gln:Asp/Asn:Val:Leu, 1:1:1:4), but the fatty acid compositions differed. Multiple regression analysis showed that the specific biosurfactant activity depended on the ratios of both iso to normal even-numbered fatty acids and anteiso to iso odd-numbered fatty acids. A multiple regression model accurately predicted the specific biosurfactant activities of four newly purified biosurfactants (r2= 0.91). The fatty acid composition of the biosurfactant produced by Bacillus subtilis subsp. subtilis strain T89-42 was altered by the addition of branched-chain amino acids to the growth medium. The specific activities of biosurfactants produced in cultures with different amino acid additions were accurately predicted by the multiple regression model derived from the fatty acid compositions (r2= 0.95). Our work shows that many strains of Bacillus mojavensis and Bacillus subtilis produce biosurfactants and that the fatty acid composition is important for biosurfactant activity.

Amino Acids↗
PubMed1992

Incomplete fatty acid oxidation. The production and epimerization of 3-hydroxy fatty acids.

3-Hydroxydicarboxylic acids are major urinary metabolites derived from fatty acid metabolism. These compounds are produced from the omega-oxidation of 3-hydroxy fatty acids. The production of the precursor 3-hydroxy fatty acids from incomplete beta-oxidation of fatty acids in rat liver mitochondria was investigated. Independent of the chain length or the concentration of fatty acid substrates, the accumulation of 3-hydroxyacyl intermediates was relatively constant at the concentration of 3-5 nmol/mg of mitochondrial protein. The extent of the incomplete oxidation was the same in Percoll gradient-purified mitochondria. Rotenone treatment increased the production of 3-hydroxy fatty acids. 3-Hydroxy fatty acids did not exist as pure L-enantiomer as expected from beta-oxidation. Instead, these metabolites were epimerized to a near racemic mixture of D- and L-isomers with a slightly dominant D-isomer (58 +/- 3%). By using deuterium-isotope labeling, the mechanism of epimerizartion was shown to be a rapid dehydration-rehydration through trans-2-enoyl-CoA. In addition, cis-3 and trans-3 fatty acids were produced; these metabolites were derived from the isomerization of trans-2-enoyl-CoA. Epimerase and isomerase were thought to be enzymes involved in the oxidation of unsaturated fatty acids. Current data have shown that the metabolism of these acids is actually through NADPH-dependent reduction pathways. The activities of epimerase and isomerase detected in rat liver mitochondria possibly function mainly in the metabolism of saturated fatty acids in a reverse role to the conventional concept.

Animals↗
PubMed2004

Synthesis of sequential polydepsipeptides utilizing a new approach for the synthesis of depsipeptides.

Sequential polydepsipeptides were synthesized by the depsipeptide active ester method using a new approach for the direct synthesis of N-protected depsipeptide free acids from hydroxy acids. The method uses synthesis of Boc-didepsipeptides by reaction of free hydroxy acids with Boc-amino acid N-hydroxysuccinimide esters catalyzed by 4-dimethylaminopyridine and chain elongation of the free depsipeptides by the reaction with Boc-amino acid N-hydroxysuccinimide esters in an organic solvent system of acetonitrile-tetrahydrofuran. The Boc-depsipeptide free acids were activated as their N-hydroxysuccinimide esters, which were polymerized after removal of the Boc-protecting group.

4-Aminopyridine↗
PubMed1984

Rapid and simple method for the simultaneous determination of 3,4-dihydroxyphenylacetic acid, 5-hydroxyindole-3-acetic acid and 4-hydroxy-3-methoxyphenylacetic acid in human plasma by high-performance liquid chromatography with electrochemical detection.

A simple procedure for the simultaneous determination of major metabolites of dopamine and serotonin in plasma, i.e. 3,4-dihydroxyphenylacetic acid, 5-hydroxyindole-3-acetic acid, and 4-hydroxy-3-methoxyphenylacetic acid, was developed. The method is based on rapid isolation of the compounds by one-step clean-up on a small C18 column, followed by high-performance liquid chromatography with dual electrochemical detection. The system is readily used for clinical applications.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2002

Purification and characterization of a Galactomyces reessii hydratase that converts 3-methylcrotonic acid to 3-hydroxy-3-methylbutyric acid.

Cell free extracts of Galactomyces reessii contain a hydratase as the key enzyme for the transformation of 3-methylcrotonic acid to 3-hydroxy-3-methylbutyric acid. Highest levels of hydratase activity were obtained during growth on isovaleric acid. The enzyme, an enoyl CoA hydratase, was purified 147-fold by precipitation with ammonium sulphate and successive chromatography over columns of DE-52, Blue Sepharose CL-6B and Sephacryl S-200. During purification, hydratase activity was measured spectrophotometrically (OD change at 263 nm) for 3-methylcrotonyl CoA and crotonyl CoA as substrates. The enzyme displayed highest activity with crotonyl CoA with a Kcat of 1,050,000 min(-1). The ratio of crotonyl CoA to 3-methylcrotonyl CoA activities was constant (20:1) during all steps of purification. The Kcat for crotonyl CoA was also about 20 times greater than the Kcat for 3-methylcrotonyl CoA (51,700 min(-1). The enzyme had pH and temperature optima at 7.0 and 35 degrees C, a native Mr of 260 +/- 4.5 kDa and a subunit Mr of 65 kDa, suggesting that the enzyme was a homotetramer. The pI of the purified hydratase was 5.5, and the N-terminal amino acid sequence was VPEGYAEDLLKGKMMRFFDS. Hydratase activity for 3-methylcrotonyl CoA was competitively inhibited by acetyl CoA, propionyl CoA and acetoacetyl CoA.

Amino Acid Sequence↗
PubMed1982

Gas chromatographic-mass spectrometric analysis of organic acids in renal tissue biopsy: identification of 4-hydroxybutyric acid and 4-hydroxy-2-butenoic acid.

The organic acids in renal tissue biopsy (0.5-1 mg) obtained from chronic glomerulonephritis patients were analyzed capillary column gas chromatography--mass spectrometry. Some twenty compounds were identified in the renal tissue. The organic acid profile of renal tissue showed a marked difference from those of urine and serum. In particular, 4-hydroxybutyric acid and 4-hydroxy-2-butenoic acid, which are usually undetectable in urine and serum, were detected for the first time in renal tissue in considerably large amounts.

Biopsy↗
PubMed1973

Occurrence of branched-cahin hydroxy fatty acids in Pseudomonas maltophilia.

Three branched-chain hydroxy acids not previously reported in other bacteria were found in extracts from saponified whole cells of Pseudomonas maltophilia. On the basis of evidence from mass spectrometry, infrared spectroscopy, and gas chromatographic procedures, they were identified as 2-hydroxy-9-methyldecanoic acid, 3-hydroxy-9-methyldecanoic acid, and 3-hydroxy-11-methyldodecanoic acid. These acids appeared to be tightly bound to other cellular components since they were not extracted from lyophilized cells with a chloroform-methanol (3:1) mixture.

Bromine↗
PubMed1996

Hepatic biotransformation in rodents and physicochemical properties of 23(R)-hydroxychenodeoxycholic acid, a natural alpha-hydroxy bile acid.

The hepatic biotransformation in the rat and hamster of 23(R)-hydroxychenodeoxycholic acid (23(R)OH-CDCA), the alpha-hydroxy derivative of CDCA, was defined; some physiological and physicochemical properties were also assessed. 23(R)OH-CDCA was isolated from duck bile; [24-14C]23(R)OH-CDCA was synthesized. The compound was administered intravenously to anesthetized biliary fistula rats at doses of 1, 3, or 5 mu mol/kg-min and to hamsters at 3 mu mol/min-kg. Biliary bile acids and radioactivity were analyzed by thin-layer chromatography (TLC), high pressure liquid chromatography (HPLC), and gas chromatography-mass spectrometry (GC-MS). Recovery of radioactivity in bile was incomplete (50-70% of infused dose); some was also recovered as breath 14CO2. Radioactivity in bile was present as unchanged compound (25-50%, dose-dependent) and its conjugates (with taurine, with glycine, or with glucuronate). Nor-CDCA (C23) was present in bile (in both unconjugated and conjugated form), indicating that 23(R)OH-CDCA had undergone oxidative decarboxylation (alpha-oxidation) with loss of the C-24 carboxyl group. The alpha-oxidation was 20 +/- 5% (mean +/- SD) of administered dose in the rat and was not dose-dependent; in hamsters, alpha-oxidation was 35 +/- 8%. In rats, the S isomer of 23OH-CDCA also underwent alpha-oxidation (10 +/- 2%). Nor-CDCA also underwent 6beta-hydroxylation to form nor-alpha-muricholic acid, as well as reduction of its C-23 carboxyl group to form the C23 alcohol. The taurine conjugate of 23(R)OH-CDCA [23(R)OH-CDC-tau] was prepared synthetically and characterized by 1H-NMR. By surface tension measurements, it had a critical micellization concentration (CMC) of 3.5 mM (in 0.15 M Na+), as compared to 1.8 mM for CDC-taurine. Aqueous solubility of 23(R)OH-CDCA increased markedly above pH 5, compared to pH 7 for CDCA. When incubated with cholylglycine hydrolase, 23(R)OH-CDC-tau was deconjugated at a rate one-fourth that of CDC-tau. It is concluded that the presence of a 23(R)-hydroxyl group in a 3alpha, 7alpha-dihydroxy bile acid alters its metabolism in the rodent hepatocyte, as evidenced by inefficient conjugation with taurine or glycine, alpha-oxidation to nor (C23) bile acid, and reduction of the nor bile acid to the primary alcohol. The taurine conjugate of 23(R)OH-CDCA, a major biliary bile acid of marine mammals and wading birds, is a biological detergent with properties superior to those of the taurine conjugate of CDCA. Natural C23 nor-bile acids may be formed by alpha-oxidation of alpha-hydroxy C24 bile acids.

Animals↗
PubMed1991

Synthesis and antimicrobial activity of hydroxy-isophthalaldehyde acid derivatives.

4-hydroxy-isophthalaldehyde acid (1), its alkyl esters (methyl, ethyl, propyl and butyl) and alkyl ethers (propyl, butyl, pentyl and esyl), as well as 6-hydroxy-isophthalaldehyde acid (2) ita alkyl esters (methyl and ethyl), 4-hydroxy-5-iodo-isophthalaldehyde acid (3) and its methyl ester were synthesized and characterized. Antimicrobial and antifungal activity was tested and the LD50 of the most active compound 4 was determined.

Animals↗
PubMed1980

Stereochemistry in the formation of 9-hydroxy-10,12-octadecadienoic acid and 13-hydroxy-9,11-octadecadienoic acid from linoleic acid by fatty acid cyclooxygenase.

9-Hydroxy-10,12-octadecadienoic acid and 13-hydroxy-9,11-octadecadienoic acid are formed from linoleic acid upon incubation with the microsomal fraction of homogenates of the sheep vesicular gland (Hamberg, M. and Samuelsson, B. (1967) J. Biol. Chem. 242, 5344-5354. This communication is concerned with the stereochemical aspects of the conversion. The ratio between the 9- and 13-hydroxy isomers was 77:23. Steric analysis of the individual isomers showed that the hydroxyl group of both isomers had mainly the L configuration, i.e. 9L:9D, 79:21 and 13L:13D, 9- and 13-hydroxyoctadecadienoates which had largely lost the tritium label (6% and 7% retention of tritium relative to precursor, respectively) showing that the hydrogen which is removed from C-11 during the conversion has the L (pro-S) configuration.

Animals↗