In Vitro system for the study of bacteriophage phi chi 174 adsorption and eclipse.

An in vitro system was developed for the study of the initial stages of bacteriophage phi chi 174 infection. Escherichia coli C cells were incubated with 20% sucrose and then subjected to cold osmotic shock in 5 mM MgSO4. The concentrated supernatant shock fluid inactivated phi chi 174 with the same kinetics and requirements as for normal infection. Shock fluids prepared from phi chi 174-resistant strains of E. coli did not show this effect. The 114S phage were initially converted into 70S particles, the process termed "eclipse". These structurally altered phages then attached to a component of the shock fluid, producing fast-sedimenting complexes, and eventually released at least a part of their DNA into the medium. The fast-sedimenting complex could be radioactively labeled with oleic acid. Radioactivity was found to co-chromatograph with both biological activity and the majority of the high-molecular-weight carbohydrates present in the shock fluid. It is concluded that E. coli C osmotic shock fluid contains isolated phi chi 174-specific receptor sites composed of lipopolysaccharides. This system conveniently separates the early stages of phage phi chi 174 infection from the intracellular events.     

Changes in the cell size of Escherichia coli M-17 during induced destruction

The autolysis of E. coli, induced by their deprivation of nutrition in combination with the action of oleic acid and a temperature of 45 degrees C, was studied. The study revealed that an increase in the number of cells during 4 hours after the induction of the process was accompanied by a decrease in their size and an increase in the surface/volume ratio. Changes in the size of bacteria in the course of induced destruction resulting from their deprivation of nutrition in combination the action of oleic acid and a temperature of 45 degrees C were found to occur in two phases: (1) a decrease in size with an increase in the surface/volume ratio; (2) an increase in size with a decrease in the surface/volume ratio.     

The action of human and rabbit serum phospholipase A2 on Escherichia coli phospholipids

We have compared the properties of phospholipase A (E.C. 3.1.1.4) activity in whole human and rabbit serum toward the phospholipids of Escherichia coli. Using as substrate E. coli labeled during growth with either [1-(14)C]-palmitic acid or [1-(14)C]oleic acid, and then autoclaved to inactivate E. coli phospholipases and to render the labeled phospholipids accessible to exogenous phospholipases, we show that the deacylating activity in both human and rabbit serum is almost exclusively of the A(2) type. Rabbit serum is at least 20-fold more active than human serum. Activity in both sera is maximal at physiological Ca(2+) concentrations (2 mM) and is abolished by ethylenediaminetetraacetic acid. To examine hydrolysis of intact (unautoclaved) E. coli treated with 25% serum, use was made of a phospholipase A-deficient E. coli strain (E. coli S17), thereby eliminating the possible contribution of bacterial phospholipases to degradation. Human and rabbit serum are about equally bactericidal toward E. coli and cause comparable structural damage. However, only rabbit serum produces substantial hydrolysis of the phospholipids of intact E. coli S17. Heated (56 degrees C, 30 min) rabbit serum is non-bactericidal and retains phospholipase A(2) activity toward autoclaved, but not intact E. coli. The ability of heated serum to degrade phospholipids of intact E. coli S17 is restored, however, by adding 25% normal human serum, which is bactericidal. In this combination, doses of heated rabbit serum containing as much phospholipase A(2) activity (toward autoclaved E. coli) as is present in 25% unheated rabbit serum, produce roughly the same extent of hydrolysis of intact E. coli as does normal rabbit serum alone. Low doses with a phospholipase A(2) activity comparable to that of normal human serum elicit little or no hydrolysis. These findings indicate that hydrolysis of the phospholipids of intact E. coli S17 by serum occurs when: 1) the serum is bactericidal, and 2) when sufficient phospholipase A(2) is present. The difference in phospholipid hydrolysis that accompanies killing of E. coli by human or rabbit serum appears to reflect, therefore, the different amounts of phospholipase A(2) activity in the two sera. Phospholipid degradation is not required for the bactericidal action of serum. Bacterial phospholipid breakdown may be important, however, in the overall destruction and digestion of invading bacteria by the host.-Kaplan-Harris, L., J. Weiss, C. Mooney, S. Beckerdite-Quagliata, and P. Elsbach. The action of human and rabbit serum phospholipase A(2) on Escherichia coli phospholipids.     

Influence of unsaturated fatty acid membrane component on sensitivity of an Escherichia coli fatty acid auxotroph to conditions of nutrient depletion

The unsaturated fatty acid auxotroph Escherichia coli AK7 was provided with either oleic acid (cis 18:1) or linolenic acid (cis 18:3) to vary the degree of unsaturation of cell membrane lipids. The susceptibility of oleic acid- and linolenic acid-grown cells to starvation at 37 degrees C in 154 mM NaCl was compared following the decline in the number of CFU by plating the cells on agar medium. The decline in CFU was faster for linolenic acid-than for oleic acid-grown cells, but it was not indicative of cell death, since culturable CFU was recovered after respirable substrate was added to the starved cell suspension. Cell envelope microviscosity (determined by fluorescence polarization) of oleic acid- and linolenic acid-grown cells was equal in the presence of a respirable substrate, but in its absence the microviscosity of linolenic acid-grown cells was lower than that of oleic acid-grown cells. The results suggest that cell envelope microviscosity is an important factor in determining the sensitivity of E. coli to conditions of nutrient depletion.     

Influence of unsaturated fatty acid membrane component on sensitivity of an Escherichia coli fatty acid auxotroph to conditions of nutrient depletion.

The unsaturated fatty acid auxotroph Escherichia coli AK7 was provided with either oleic acid (cis 18:1) or linolenic acid (cis 18:3) to vary the degree of unsaturation of cell membrane lipids. The susceptibility of oleic acid- and linolenic acid-grown cells to starvation at 37 degrees C in 154 mM NaCl was compared following the decline in the number of CFU by plating the cells on agar medium. The decline in CFU was faster for linolenic acid-than for oleic acid-grown cells, but it was not indicative of cell death, since culturable CFU was recovered after respirable substrate was added to the starved cell suspension. Cell envelope microviscosity (determined by fluorescence polarization) of oleic acid- and linolenic acid-grown cells was equal in the presence of a respirable substrate, but in its absence the microviscosity of linolenic acid-grown cells was lower than that of oleic acid-grown cells. The results suggest that cell envelope microviscosity is an important factor in determining the sensitivity of E. coli to conditions of nutrient depletion.     

Conjugated polyene fatty acids as fluorescent probes: biosynthetic incorporation of parinaric acid by Escherichia coli and studies of phase transitions.

The use of the fluorescent fatty acid, parinaric acid (9, 11, 13, 15-octadecatetraenoic acid) (PnA), was studied in cells of an unsaturated fatty acid auxotroph of Escherichia coli. Growth conditions were found that permitted biosynthetic incorporation of PnA (up to 3%) into membrane phospholipids during growth on oleic or elaidic acid. Fluorescence measurements of incorporated PnA revealed phase transitions in cells, membranes, and phospholipids at temperatures that reflected the fatty acid composition of the sample. Transitions had a well-defined onset from high temperature, while the lower and end point was less well defined. cis- and trans-PnA (cis, trnas, trans, cis, and all trans, respectively) gave comparable results. Similar phase transitions were detected with PnA, which was not biosynthetically incorporated. Fluorescence of tryptophan was measured in E. coli membranes as a function of concentration of PnA. Significant quenching of tryptophan fluorescence by PnA was observed.     

Identification and characterization of Escherichia coli thioesterase III that functions in fatty acid beta-oxidation

When Escherichia coli is grown on oleic acid as the sole carbon source, most of this fatty acid is completely degraded by beta-oxidation. However, approximately 10% of the oleic acid is only partially degraded to 3,5- cis-tetradecadienoyl-CoA, which is hydrolyzed to 3,5- cis-tetradecadienoic acid and released into the growth medium. An investigation of thioesterases involved in this novel pathway of beta-oxidation led to the identification of a new thioesterase (thioesterase III) that is induced by growth of E. coli on oleic acid. This enzyme was partially purified and identified as the ybaW gene product by mass spectrometric analysis of tryptic peptides. The ybaW gene, which has a putative consensus sequence for binding the fatty acid degradation repressor, was cloned and expressed in E. coli. Thioesterase III was shown to be a long-chain acyl-CoA thioesterase that is most active with 3,5-tetradecadienoyl-CoA, a minor metabolite of oleate beta-oxidation. Its substrate specificity and induction by fatty acids agree with its proposed function in the thioesterase-dependent pathway of beta-oxidation. Thioesterase III is proposed to hydrolyze metabolites of beta-oxidation that are resistant to further degradation and that would inhibit the flux through the pathway if they were allowed to accumulate.     

Production of 10-hydroxystearic acid from oleic acid by whole cells of recombinant Escherichia coli containing oleate hydratase from Stenotrophomonas maltophilia

A putative fatty acid hydratase from Stenotrophomonas maltophilia was cloned and expressed in Escherichia coli. The recombinant enzyme showed the highest hydration activity for oleic acid among the fatty acids tested, indicating that the enzyme is an oleate hydratase. The optimal conditions for the production of 10-hydroxystearic acid from oleic acid using whole cells of recombinant E. coli containing the oleate hydratase were pH 6.5, 35°C, 0.05% (w/v) Tween 40, 10 g l(-1) cells, and 50 g l(-1) oleic acid. Under these conditions, whole recombinant cells produced 49 g l(-1) 10-hydroxystearic acid for 4 h, with a conversion yield of 98% (w/w), a volumetric productivity of 12.3 g l(-1) h(-1), and a specific productivity of 1.23 g g-cells(-1) h(-1), which were 18%, 2.5-, and 2.5-fold higher than those of whole wild-type S. maltophilia cells, respectively. This is the first report of 10-hydroxystearic acid production using recombinant cells and the concentration and productivity are the highest reported thus far among cells.     

Inhibitory Effect of Fatty Acids on the Entry of the Lipid-Containing Bacteriophage PR4 into Escherichia coli

Various unsaturated fatty acids (notably palmitoleic acid and oleic acid) interfered with plaque production by the lipid-containing bacteriophage PR4 on lawns of Escherichia coli. Addition of fatty acid to give 50 mug/ml ( approximately 0.2 mM) at the time of infection prevented phage replication. If, however, the fatty acid was added after infection, normal amounts of phage were produced. If the fatty acid was added (to 50 mug/ml) to the host cell culture a long enough time before infection such that the fatty acid concentration in the growth medium at the time of infection was reduced to less, similar5 mug/ml (due to fatty acid incorporation by the host cells), normal phage replication occurred also. Neither palmitoleic acid nor oleic acid prevented PR4 attachment to E. coli. Several types of experiments indicated that it is the entry process of the virus that is inhibited by these fatty acids. Specifically, if the fatty acid was added at the time of infection, the host cells were not killed by the virus and no detectable amounts of viral protein were synthesized. In addition, experiments using purified radioisotope-labeled virions showed directly that entry is inhibited. Mutants of PR4 that did replicate in the presence of oleic acid arose spontaneously at a frequency of 10(-6). Three of these mutants that have been further characterized have protein and phospholipid compositions indistinguishable from those of wild-type PR4.     

The incorporation of oleic and linoleic acids and their desaturation products into the glycerolipids of maize leaves

[1-¹⁴C]Oleic and [1-¹⁴C]linoleic acids were rapidly desaturated when incubated with maize leaves from 8-day-old plants and the labeled fatty acids, and their desaturation products, were rapidly incorporated into glycerolipids. Oleic acid was desaturated to linoleate at the rate of 0.7 nmol/100 mg tissue/h and further desaturated to linolenate at about one-third this rate. The rates of linolenate formation were similar when either oleic acid or linoleic acid was the substrate although there was a 2-h lag period when oleic acid was substrate. When radioactive oleic, linoleic, and linolenic acids were substrates, phosphatidylcholine was the most extensively labeled glycerolipid followed by monogalactosyldiacylglycerol. The relative rates of incorporation of label into individual glycerolipids are consistent with a movement of labeled fatty acids from phosphatidylcholine to monogalactosyldiacylglycerol and then to diagalactosyldiacylglycerol. The rates of labeling of phosphatidylcholine oleate and of phosphatidylcholine linoleate are consistent with a precursor-product relationship in that there was a delayed accumulation of phosphatidylcholine linoleate relative to that of phosphatidylcholine oleate and phosphatidylcholine linoleate continued to accumulate while phosphatidylcholine oleate declined. Linoleate formed from oleate was widely distributed in glycerolipids but neither phosphatidylcholine linolenate nor linolenate-containing diacylglycerol was detected at short and intermediate incubation times when either oleic or linoleic acid was substrate. The kinetics of incorporation of linoleate and linolenate into monogalactosyldiacylglycerol suggest a transfer of linoleate from phosphatidylcholine. The initial rate of accumulation of labeled linolenate in monogalactosyldiacylglycerol was very similar to the rate of desaturation of linoleate and it is suggested that desaturation of linoleate occurs while associated with monogalactosyl-diacylglycerol.     

Hemodynamic effects of oleic acid in newborn lambs: role of arachidonic acid metabolites.

Oleic acid injection produces acute lung injury and pulmonary hypertension in adult animals. In other types of acute lung injury, such as that caused by E. coli endotoxin, metabolites of arachidonic acid are important mediators of pulmonary hypertension. In order to understand the hemodynamic response of newborn animals to oleic acid injection and the contribution of arachidonic acid metabolites to that response, we injected oleic acid into awake, chronically instrumented newborn lambs. The hemodynamic response of lambs to injections of oleic acid alone was compared to their response after pretreatment with either FPL57231, a putative leukotriene receptor antagonist, or indomethacin, a cyclooxygenase synthesis inhibitor. Oleic acid caused acute pulmonary hypertension associated with an increase in protein-rich lung lymph fluid. Systemic hemodynamic effects were variable. FPL57231 completely blocked the oleic acid-induced pulmonary hypertension while indomethacin significantly attenuated the response. Therefore, metabolites of arachidonic acid metabolism appear to be important mediators of oleic acid-induced pulmonary hypertension in newborn lambs.     

Amino acid sequence of the regulatory-site glyoxylate peptide of biodegradative threonine dehydratase of Escherichia coli.

Incubation of purified Escherichia coli biodegradative threonine dehydratase with glyoxylate resulted in covalent binding of 1 mol of glyoxylate per mol of protein with concomitant loss of enzyme activity. The glyoxylate-binding site was identified as a heptapeptide representing amino acid residues Ser-33-Asn-Tyr-Phe-Ser-Glu-Arg-39 in the protein primary structure. Addition of glyoxylate to a culture of E. coli cells led to time-dependent enzyme inactivation. Immunoprecipitation with anti-dehydratase antibody of extract from [14C]glyoxylate-treated cells revealed labeled dehydratase polypeptide. These results are interpreted to mean that enzyme inactivation by glyoxylate in E. coli cells is associated with covalent protein modification.     

Novel aerobic tetracycline resistance gene that chemically modifies tetracycline.

A tetracycline resistance gene that was found originally on the Bacteroides plasmid pBF4 confers resistance on Escherichia coli but only when cells are growing aerobically. When E. coli EM24 carrying this aerobic tetracycline resistance (*Tcr) gene is grown in medium containing tetracycline, the resulting spent medium is no longer toxic to tetracycline-sensitive (Tcs) E. coli EM24 (B.S. Speer and A.A. Salyers, J. Bacteriol. 170: 1423-1429, 1988). To determine whether the *Tcr gene product modified tetracycline, we characterized the material resulting from incubation of E. coli (*Tcr) with tetracycline. When [7-3H(N)]tetracycline was added to cultures of E. coli (*Tcr), at least 90% of the label was recovered in the extracellular fluid. Therefore, tetracycline was not being sequestered by the cells. The labeled material behaved similarly to tetracycline with respect to solubility in various organic solvents. However, the UV-visible light spectrum had a single peak at 258 nm, whereas the tetracycline spectrum had a peak at 364 nm. The labeled material also had a faster migration rate than did tetracycline on thin-layer plates in a solvent system of butanol-methanol-10% citric acid (4:1:2, vol/vol/vol) and was separable from tetracycline by reverse-phase high-pressure liquid chromatography, using an acetronitrile-0.1% trifluoroacetic acid solvent system. These results demonstrate that the *Tcr gene product chemically modifies tetracycline. The *Tcr gene is the first example of a chemically modifying tetracycline resistance mechanism.     

Patterns of bacterial destruction in solutions by microwave irradiation

The patterns of destruction of several kinds of bacterial cells suspended in solutions by microwave irradiation were studied. The survival curves of Escherichia coli and Staphylococcus aureus were similar and approximated a set of three linear phases. The curves of Pseudomonas fluorescens and Bacillus cereus spores shifted to the shorter and longer irradiation periods, respectively. The rate constant and initial time of destruction for each linear phase of the survival curve were compared among these organisms. When irradiated E. coli cells were incubated in an agar with a high salt level, fewer cells were recovered. The curve of E. coli cells in the logarithmic phase of growth shifted to shorter exposure periods. There were no significant differences in the survival curves of E. coli cells grown at temperatures of 22–36°C, whereas the curve of cells grown at 44°C shifted to longer periods.     

The beta-oxidation systems of Escherichia coli and Salmonella enterica are not functionally equivalent

Based on its genome sequence, the pathway of beta-oxidative fatty acid degradation in Salmonella enterica serovar Typhimurium LT2 has been thought to be identical to the well-characterized Escherichia coli K-12 system. We report that wild-type strains of S. enterica grow on decanoic acid, whereas wild-type E. coli strains cannot. Mutant strains (carrying fadR) of both organisms in which the genes of fatty acid degradation (fad) are expressed constitutively are readily isolated. The S. enterica fadR strains grow more rapidly than the wild-type strains on decanoic acid and also grow well on octanoic and hexanoic acids (which do not support growth of wild-type strains). By contrast, E. coli fadR strains grow well on decanoic acid but grow only exceedingly slowly on octanoic acid and fail to grow at all on hexanoic acid. The two wild-type organisms also differed in the ability to grow on oleic acid when FadR was overexpressed. Under these superrepression conditions, E. coli failed to grow, whereas S. enterica grew well. Exchange of the wild-type fadR genes between the two organisms showed this to be a property of S. enterica rather than of the FadR proteins per se. This difference in growth was attributed to S. enterica having higher cytosolic levels of the inducing ligands, long-chain acyl coenzyme As (acyl-CoAs). The most striking results were the differences in the compositions of CoA metabolites of strains grown with octanoic acid or oleic acid. S. enterica cleanly converted all of the acid to acetyl-CoA, whereas E. coli accumulated high levels of intermediate-chain-length products. Exchange of homologous genes between the two organisms showed that the S. enterica FadE and FadBA enzymes were responsible for the greater efficiency of beta-oxidation relative to that of E. coli.     

Metabolic transformation of labelled exogenous fatty acids by fungal cultures of the family Entomophthoraceae

Entomophthora coronata 1932 and E. conica 1716 are quite different in their fatty acid composition and the unsaturation degree of synthesized lipids. The cultures were used as models to study metabolic transformations of exogenous 14C-labeled acetic, palmitic, stearic and oleic acids as well as to compare the activities of the synthetase and desaturase enzyme complexes. The cultures were capable of transforming exogenous acetic and fatty acids into polyunsaturated arachidonic acid. E. coronata 1932 whose lipids mainly contain fatty acids with a short chain could metabolize unsaturated oleic acid to yield polyene fatty acids. However, this culture metabolized exogenous acids at a far lower rate as compared with E. conica 1716. The high content of saturated fatty acids with a short chain in the lipids might be due to the specific action of the synthetase complex and to the low activity of the desaturation enzymes. It has been demonstrated for the first time that exogenous oleic acid is converted at a high rate by the cells into arachidonic acid, a precursor of prostaglandin compounds.     

Reduction of carboxylic acids by Nocardia aldehyde oxidoreductase requires a phosphopantetheinylated enzyme

Aldehyde oxidoreductase (carboxylic acid reductase (Car)) catalyzes the magnesium-, ATP-, and NADPH-dependent reduction of carboxylic acids to their corresponding aldehydes. Heterologous expression of the car gene in Escherichia coli afforded purified recombinant enzyme with a specific activity nearly 50-fold lower than that of purified native Nocardia sp. enzyme. The 5-fold increase in specific activity obtained by incubating purified recombinant Car with CoA and Nocardia cell-free extracts indicated that post-translational phosphopantetheinylation of Car is required for maximum enzyme activity. Nocardia phosphopantetheine transferase (PPTase) expressed in E. coli was isolated and characterized. When incubated with [(3)H]acetyl-CoA and Nocardia PPTase, the labeled acetylphosphopantetheine moiety was incorporated into recombinant Car. Coexpression of Nocardia Car and PPTase in E. coli gave a reductase with nearly 20-fold higher specific activity. Site-directed mutagenesis in which Ser(689) was replaced with Ala resulted in an inactive Car mutant. The results show that Car expressed in Escherichia coli is an apoenzyme that is converted to a holoenzyme by post-translational modification via phosphopantetheinylation. Doubly recombinant resting E. coli cells efficiently reduce vanillic acid to vanillin.     

Fatty acid degradation in Caulobacter crescentus.

Fatty acid degradation was investigated in Caulobacter crescentus, a bacterium that exhibits membrane-mediated differentiation events. Two strains of C. crescentus were shown to utilize oleic acid as sole carbon source. Five enzymes of the fatty acid beta-oxidation pathway, acyl-coenzyme A (CoA) synthase, crotonase, thiolase, beta-hydroxyacyl-CoA dehydrogenase, and acyl-CoA dehydrogenase, were identified. The activities of these enzymes were significantly higher in C. crescentus than the fully induced levels observed in Escherichia coli. Growth in glucose or glucose plus oleic acid decreased fatty acid uptake and lowered the specific activity of the enzymes involved in beta-oxidation by 2- to 3-fold, in contrast to the 50-fold glucose repression found in E. coli. The mild glucose repression of the acyl-CoA synthase was reversed by exogenous dibutyryl cyclic AMP. Acyl-CoA synthase activity was shown to be the same in oleic acid-grown cells and in cells grown in the presence of succinate, a carbon source not affected by catabolite repression. Thus, fatty acid degradation by the beta-oxidation pathway is constitutive in C. crescentus and is only mildly affected by growth in the presence of glucose. Tn5 insertion mutants unable to form colonies when oleic acid was the sole carbon source were isolated. However, these mutants efficiently transported fatty acids and had beta-oxidation enzyme levels comparable with that of the wild type. Our inability to obtain fatty acid degradation mutants after a wide search, coupled with the high constitutive levels of the beta-oxidation enzymes, suggest that fatty acid turnover, as has proven to be the case fatty acid biosynthesis, might play an essential role in membrane biogenesis and cell cycle events in C. crescentus.     

An alternative pathway of oleate beta-oxidation in Escherichia coli involving the hydrolysis of a dead end intermediate by a thioesterase

The degradation of 2-trans,5-cis-tetradecadienoyl-CoA, a metabolite of oleic acid, by the purified complex of fatty acid oxidation from Escherichia coli was studied to determine how much of the metabolite is converted to 3,5-cis-tetradecadienoyl-CoA and thereby diverted from the classical, isomerase-dependent pathway of oleate beta-oxidation. Approximately 10% of the 2,5-intermediate was converted to the 3,5-isomer. When the latter compound was allowed to accumulate, it strongly inhibited the flux through the main pathway. Since Delta(3,5),Delta(2,4)-dienoyl-CoA isomerase was not detected in E. coli cells grown on oleate, the 3,5-intermediate cannot be metabolized via the reductase-dependent pathway. However, it was hydrolyzed by a thioesterase, which was most active with 3,5-cis-tetradecadienoyl-CoA as substrate and which was induced by growth of E. coli on oleate. An analysis of fatty acids present in the medium after growth of E. coli on oleate revealed the presence of 3,5-tetradecadienoate, which was not detected after cells were grown on palmitate or glucose. Altogether, these data prompt the conclusion that oleate is mostly degraded via the classical, isomerase-dependent pathway in E. coli but that a small amount of 2-trans,5-cis-tetradecadienoyl-CoA is diverted from the pathway via conversion to 3,5-cis-tetradecadienoyl-CoA by Delta(3),Delta(2)-enoyl-CoA isomerase. The 3,5-intermediate, which would strongly inhibit beta-oxidation if allowed to accumulate, is hydrolyzed, and the resultant 3,5-tetradecadienoate is excreted into the growth medium. This study provides evidence for the novel function of a thioesterase in beta-oxidation.     

Candida cloacae长链脂肪酸醇氧化酶基因的克隆与表达

Ｃａｎｄｉｄａｃｌｏａｃａｅ是利用链烃和长链脂肪酸作为碳源来生长的一种工业酵母 .长链脂肪酸在单加氧酶作用下 ,使远离羧基的甲基羟化 ,生成ω 羟脂肪酸 .后者在生物体中通过两条连续的氧化通路进行氧化 (ω氧化通路和 β氧化通路 ) .醇氧化酶是ω氧化通路中的重要组成酶 ,它可以催化链烃或长链脂肪酸分子中的羟基氧化为醛基 ,后者再经其它酶氧化为羧基 .长链脂肪酸通过ω氧化通路生成二羧基化合物 ,它可作为重要的化工原料 ,广泛应用于香料、多聚酰胺、多聚酯、胶类和环内酯抗生素的生成[1] .ω氧化通路中产生的羧基化合物再经 β 氧…