8-Phenyloctanoic acid

Microbial synthesis of poly(beta-hydroxyalkanoates) bearing phenyl groups from pseudomonas putida: chemical structure and characterization.[Pubmed:11749221]

Biomacromolecules. 2001 Summer;2(2):562-7.

New poly(beta-hydroxyalkanoates) having aromatics groups (so-called PHPhAs) from a microbial origin have been characterized. These polymers were produced and accumulated as reserve materials when a beta-oxidation mutant of Pseudomonas putida U, disrupted in the gene that encodes the 3-ketoacyl-CoA thiolase (fadA), was cultured in a chemically defined medium containing different aromatic fatty acids (6-phenylhexanoic acid, 7-phenylheptanoic acid, a mixture of them, or 8-Phenyloctanoic acid) as carbon sources. The polymers were extracted from the bacteria, purified and characterized by using (13)C nuclear magnetic resonance spectroscopy (NMR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). Structural studies revealed that when 6-phenylhexanoic acid was added to the cultures, an homopolymer (poly-3-hydroxy-6-phenylhexanoate) was accumulated. The feeding with 8-Phenyloctanoic acid and 7-phenylheptanoic acid leads to the formation of copolymers of the corresponding units with the n - 2 carbons formed after deacetylation, copoly(3-hydroxy-8-phenyloctanoate-3-hydroxy-6-phenylhexanoate) and copoly(3-hydroxy-7-phenylheptanoate-3-hydroxy-5-phenylvalerate), respectively. The mixture of 6-phenylhexanoic acid and 7-phenylheptanoic acid gave rise to the corresponding terpolymer, copoly(3-hydroxy-7-phenylheptanoate-3-hydroxy-6-phenylhexanoate-3-hydroxy-5-pheny lvalerate). Studies on the chemical structure of these three polyesters revealed that they were true copolymers but not a mixture of homopolymers and that the different monomeric units were randomly incorporated in the macromolecular chains. Thermal behavior and molecular weight distribution were also discussed. These compounds had a dual attractive interest in function of (i) their broad use as biodegradable polymers and (ii) their possible biomedical applications.

Aerobic catabolism of phenylacetic acid in Pseudomonas putida U: biochemical characterization of a specific phenylacetic acid transport system and formal demonstration that phenylacetyl-coenzyme A is a catabolic intermediate.[Pubmed:8002592]

J Bacteriol. 1994 Dec;176(24):7667-76.

The phenylacetic acid transport system (PATS) of Pseudomonas putida U was studied after this bacterium was cultured in a chemically defined medium containing phenylacetic acid (PA) as the sole carbon source. Kinetic measurement was carried out, in vivo, at 30 degrees C in 50 mM phosphate buffer (pH 7.0). Under these conditions, the uptake rate was linear for at least 3 min and the value of Km was 13 microM. The PATS is an active transport system that is strongly inhibited by 2,4-dinitrophenol, 4-nitrophenol (100%), KCN (97%), 2-nitrophenol (90%), or NaN3 (80%) added at a 1 mM final concentration (each). Glucose or D-lactate (10 mM each) increases the PATS in starved cells (140%), whereas arsenate (20 mM), NaF, or N,N'-dicyclohexylcarbodiimide (1 mM) did not cause any effect. Furthermore, the PATS is insensitive to osmotic shock. These data strongly suggest that the energy for the PATS is derived only from an electron transport system which causes an energy-rich membrane state. The thiol-containing compounds mercaptoethanol, glutathione, and dithiothreitol have no significant effect on the PATS, whereas thiol-modifying reagents such as N-ethylmaleimide and iodoacetate strongly inhibit uptake (100 and 93%, respectively). Molecular analogs of PA with a substitution (i) on the ring or (ii) on the acetyl moiety or those containing (iii) a different ring but keeping the acetyl moiety constant inhibit uptake to different extents. None of the compounds tested significantly increase the PA uptake rate except adipic acid, which greatly stimulates it (163%). The PATS is induced by PA and also, gratuitously, by some phenyl derivatives containing an even number of carbon atoms on the aliphatic moiety (4-phenyl-butyric, 6-phenylhexanoic, and 8-Phenyloctanoic acids). However, similar compounds with an odd number of carbon atoms (benzoic, 3-phenylpropionic, 5-phenylvaleric, 7-phenylheptanoic, and 9-phenylnonanoic acids) as well as many other PA derivatives do not induce the system, suggesting that the true inducer molecule is phenylacetyl-coenzyme A (PA-CoA). Furthermore, after P. putida U is cultured in the same medium containing other carbon sources (glucose or octanoic, benzoic, or 4-hydroxyphenylacetic acid) in the place of PA, the PATS and PA-CoA are not detected; neither the PATS nor PA-CoA is found in cases in which mutants (PA- and PCL-) lacking the enzyme which catalyzed the initial step of the PA degradation (phenylacetyl-CoA ligase) are used. PA-CoA has been extracted from bacteria and identified as a true PA catabolite by high-performance liquid chromatography and also enzymatically with pure acyl-CoA:6-aminopenicillanic acid acyltransferase from Penicillium chrysogenum.

[Determination of lipase with 8-phenyloctanoic acid vinyl ester as the substrate].[Pubmed:7142919]

J Clin Chem Clin Biochem. 1982 Sep;20(9):627-32.

The UV-test described by Myrick ((1976) Ph. D. Thesis, Birmingham, AL, USA) for the determination of the catalytic activity of lipase in serum, using 8-Phenyloctanoic acid vinyl ester as substrate, was investigated in detail. When tested with sera the assay gave unsatisfactory linearity. For some serum samples, evaluation was impossible, owing to the complete lack of a linear response. The substrate is attacked not only by purified pancreatic lipase, but also by liver esterase, cholinesterase in plasma, and lipoproteinlipase. Attempts to inhibit the interfering esterases with phenylmethylsulphonylfluoride were unsuccessful. Analyses of 102 sera showed no correlation with the results from the titrimetric assay (r = 0.158). Thus the method of Myrick does not provide clinically useful results.