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T M Harris

Publications and source records attributed to T M Harris.

At least 73 records · Page 4Linked to original sources
PubMed1992

Elucidation of catalytic specificities of human cytochrome P450 and glutathione S-transferase enzymes and relevance to molecular epidemiology.

A number of different approaches have been used to determine the catalytic selectivity of individual human enzymes toward procarcinogens. Studies with cytochrome P450 (P450) enzymes and glutathione S-transferases are summarized here, and recent work with pyrrolizidine alkaloids, aflatoxins, 4,4'-methylenebis(2-chloroaniline), and ethyl carbamate is discussed. In some cases a single enzyme can catalyze both activation and detoxication reactions of a chemical. The purification and characterization of human lung P4501A1 and the development of a noninvasive assay for human P4502E1 are also described.

Aflatoxin B1↗
PubMed1992

Predictors of functional outcomes after arthroscopic partial meniscectomy.

OBJECTIVE: To confirm previous studies that have identified knee osteoarthritis as the principal correlate of poor outcomes after arthroscopic partial meniscectomy (APM), we considered a range of other preoperative characteristics using multivariable analyses to control for confounding variables. METHODS: One hundred five patients who had APM were studied. Selected demographic and clinical features were obtained from charts and operative notes. Preoperative and current functional status were determined by patient interviews. The principal outcomes were functional status at the time of followup, measured by the Physical Activity Scale of the SF-36 Health Status Inventory, and the Lysholm Knee Rating Scale. RESULTS: SF-36 scores improved from a mean of 53.7 to a mean of 18.2. The percentage of patients with satisfactory (> or = 77) Lysholm scores increased from 5% preoperatively to 73%. In multivariable analyses, Worker's Compensation (p = 0.003), worse baseline physical functional status (p = 0.007), and Grade III-IV cartilage damage (p = 0.05) were associated with worse post-operative function. CONCLUSION: The outcome of APM is generally favorable. The extent of cartilage damage was confirmed as a correlate of poor outcome. However, Worker's Compensation and preoperative physical functional status had the greatest prognostic value and should be ascertained routinely in orthopedic outcome studies.

Adult↗
PubMed1990

Intercalation of aflatoxin B1 in two oligodeoxynucleotide adducts: comparative 1H NMR analysis of d(ATCAFBGAT).d(ATCGAT) and d(ATAFBGCAT)2.

8,9-Dihydro-8-(N7-guanyl-[d(ATCGAT)])-9-hydroxyaflatoxin B1.d(ATCGAT) and 8,9-dihydro-8-(N7-guanyl-[d(ATGCAT)])-9-hydroxyaflatoxin B1.8,9-dihydro-8-(N7-guanyl-[d(ATGCAT)])-9-hydroxyaflatoxin B1 were prepared by direct addition of afltoxin B1 8,9-epoxide to d(ATCGAT)2 and d(ATGCAT)2, respectively. In contrast to reaction of aflatoxin B1 8,9-epoxide with d(ATCGAT)2 which exhibits a limiting stoichiometry of 1:1 aflatoxin B1:d(ATCGAT)2 [Gopalakrishnan, S., Stone, M. P., & Harris, T. M. (1989) J. Am. Chem. Soc. 111, 7232-7239], reaction of aflatoxin B1 8,9-epoxide with d(ATGCAT)2 exhibits a limiting stoichiometry of 2:1 aflatoxin B1:d(ATGCAT)2. 1H NOE experiments, nonselective 1H T1 relaxation measurements, and 1H chemical shift perturbations demonstrate that in both modified oligodeoxynucleotides the aflatoxin moiety is intercalated above the 5'-face of the modified guanine. The oligodeoxynucleotides remain right-handed, and perturbation of the B-DNA structure is localized adjacent to the adducted guanine. Aflatoxin-oligodeoxynucleotide 1H NOEs are observed between aflatoxin and the 5'-neighbor base pair and include both the major groove and the minor groove. The aflatoxin methoxy and cyclopentenone ring protons face into the minor groove; the furofuran ring protons face into the major groove. No NOE is observed between the imino proton of the modified base pair and the imino proton of the 5'-neighbor base pair; sequential NOEs between nucleotide base and deoxyribose protons are interrupted in both oligodeoxynucleotide strands on the 5'-side of the modified guanine. The protons at C8 and C9 of the aflatoxin terminal furan ring exhibit slower spin-lattice relaxation as compared to other oligodeoxynucleotide protons, which supports the conclusion that they face into the major groove. Increased shielding is observed for aflatoxin protons; chemical shift perturbations of the oligodeoxynucleotide protons are confined to the immediate vicinity of the adducted base pair. The imidazole proton of the modified guanine exchanges with water and is observed at 9.75 ppm. The difference in reaction stoichiometry is consistent with an intercalated transition-state complex between aflatoxin B1 8,9-epoxide and B-DNA. Insertion of aflatoxin B1-8,9 epoxide above the 5'-face of guanine in d(ATCGAT)2 would prevent the binding of a second molecule of aflatoxin B1 8,9-epoxide. In contrast, two intercalation sites would be available with d(ATGCAT)2.(ABSTRACT TRUNCATED AT 400 WORDS)

Aflatoxin B1↗
PubMed1990

Pipecolic acid biosynthesis in Rhizoctonia leguminicola. I. The lysine saccharopine, delta 1-piperideine-6-carboxylic acid pathway.

The biosynthesis of pipecolic acid from L-lysine in the fungal parasite, Rhizoctonia leguminicola has been reinvestigated. Pipecolate is then utilized to form the toxic octahydroindolizine alkaloids, slaframine and swainsonine. Incorporation studies of L-versus D-[U-14C]lysine into R. leguminicola metabolites confirmed earlier findings that L-lysine is the predominant substrate for pipecolate formation and D-lysine for alpha-N-acetyllysine (concerned in lysine catabolism). However [alpha-15N]lysine, not [epsilon-15N]lysine as previously reported, labeled pipecolate. Such findings implied that delta 1-piperideine-6-carboxylate, not delta 1-piperideine-2-carboxylate, was formed from lysine and was the immediate precursor of pipecolate. Evidence from cell-free enzyme systems established the following biosynthetic events: L-lysine A----saccharopine B----delta 1-piperideine-6-carboxylate C----pipecolate. Products of reactions A and C were identified from biological and chemical considerations. Reaction B was carried out by a previously undescribed flavin enzyme termed saccharopine oxidase. The product of reaction B, which reacted with p-dimethylaminobenzaldehyde, was reduced with Na-CNB2H3. Its NMR spectrum was identical with that of deuteriated pipecolate prepared from authentic delta 1-piperideine-6-carboxylate, but not from authentic delta 1-piperideine-2-carboxylate. Reaction B represents a branching of primary lysine metabolism from saccharopine to a secondary pathway leading to pipecolate and to octahydroindolizine alkaloids in R. leguminicola.

Lysine↗
PubMed1990

Formation of prostaglandin A analogues via an allene oxide.

One potential biosynthetic route to the prostaglandins involves the participation of lipoxygenase and allene oxide synthase enzymes, giving a hydroxylated allene oxide, which then might cyclize to form prostaglandin A or a close analogue. We have tested a model of this type of transformation using 8-hydroxy-15S-hydroperoxy eicosanoids as substrates for the dehydrase (allene oxide synthase) in flaxseed. Four of these substrates, each with a 9E,11Z,13E-conjugated triene, gave an observable rate of reaction. The two derived from eicosapentaenoic acid reacted more rapidly than the corresponding arachidonic acid analogues. Also, the 8S-hydroxy-15S-hydroperoxy diastereomers reacted more rapidly than their 8R-hydroxy analogues. Products were characterized by high pressure liquid chromatography, UV, gas chromatography-mass specrometry, 1H NMR, and CD. Reaction of the (8S)-hydroxy-(15S)-hydroperoxy-eicosapentaenoic acid gave two alpha-ketols [8S),15-dihydroxy-14-oxoeicosa-5Z,9E,11Z,17Z+ ++-tetraenoic acid and the corresponding 11E isomer in a 2:1 ratio), together with four prostaglandin A3 analogues which differed in the configurations of the side chains. Oxygen 18 labeling fully supported the intermediacy of an allene oxide in the biosynthesis. The corresponding "8R" substrate was converted to the enantiomers of these products plus three 13-hydroxy-14,15-epoxy derivatives. The arachidonate analogues formed the epoxy-hydroxy derivatives, the alpha-ketols, and two prostaglandin A2 analogues with trans configuration of the side chains. These results demonstrate (i) a feasible route of metabolism of lipoxygenase products to hydroxy allene oxide, (ii) the potential for the resulting allene oxide to cyclize to a prostaglandin A analogue, and (iii) the marked influence of the hydroxyl configuration of the rate of reaction and resulting profile of products. Some of these reactions may occur in a natural pathway of prostanoid biosynthesis in corals and other organisms.

Chromatography, High Pressure Liquid↗
PubMed1990

Formation of thiol conjugates of 9-deoxy-delta 9,delta 12(E)-prostaglandin D2 and delta 12(E)-prostaglandin D2.

Albumin catalyzes the transformation of prostaglandin D2 to 9-deoxy-delta 9,delta 12(E)-prostaglandin D2 and to isomeric prostaglandin D2 compounds including delta 12(E)-prostaglandin D2. Both of these compounds are alpha,beta-unsaturated ketones, which should render them susceptible to nucleophilic addition. We therefore examined the ability of the compounds to form conjugates with thiols glutathione and cysteine. During incubation with excess glutathione, both 9-deoxy-delta 9,delta 12(E)-prostaglandin D2 and delta 12(E)-prostaglandin D2 formed a conjugate. Conjugation of 9-deoxy-delta 9,delta 12(E)-prostaglandin D2 occurred very rapidly; approximately 70% was conjugated within 2 min. In contrast, conjugation of delta 12(E)-prostaglandin D2 with glutathione proceeded at a much slower rate; only 38% was conjugated at 60 min. The formation of both conjugates was enhanced by glutathione S-transferase. Conjugation of both compounds with cysteine was found to occur more rapidly than with glutathione. This effect was more pronounced with delta 12(E)-prostaglandin D2 in which 60% conjugated with cysteine within 2 min. These differences are likely attributed to greater steric hindrance for conjugation across the delta 12 double bond compared to that across the delta 9 bond. Analysis by fast atom bombardment mass spectrometry confirmed the formation of the glutathione conjugate of 9-deoxy-delta 9,delta 12(E)-prostaglandin D2. Following prolonged incubation of 9-deoxy-delta 9,delta 12(E)-prostaglandin D2 with excess glutathione in the presence of glutathione S-transferase, a small quantity of a bis conjugate of this compound was also detected by mass spectrometry.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1990

Age variations in the relation of body mass indices to estimates of body fat and muscle mass.

In some chronic disease studies, distinctions have been made regarding the importance of body mass index (BMI) as a risk factor in younger versus older men and women. In order to determine the significance of these differences in BMI-disease associations, we determined the extent of age-dependent variations in the relation of BMIs to body composition in large probability samples of U.S. men and women from the First and Second U.S. National Health and Nutrition Examination Surveys (NHANES I and II). BMIs are more highly correlated with estimates of body fat in younger than in older men and women, and with muscle mass in older than in younger adults. Caution should be exercised in interpreting the significance of BMI as a risk factor for chronic disease, particularly in comparison of age groups.

Adipose Tissue↗
PubMed1990

Noncyclooxygenase oxidative formation of a series of novel prostaglandins: analytical ramifications for measurement of eicosanoids.

Analysis of fresh plasma from normal volunteers by negative ion chemical ionization GC/MS reveals what appear to be multiple PGF2 compounds with levels ranging from approximately 5 to 40 pg/ml. Interestingly, storage of plasma at -20 degrees C for several months was found to markedly increase the levels of these compounds to about 1000-4000 pg/ml, approximately 50-fold higher than levels detected in fresh plasma. Further studies aimed at understanding this observation revealed that alkaline hydrolysis of plasma lipids also yielded quantities of these compounds in the range that were detected in stored plasma. Employing a number of approaches such as deuteriated derivatives, hydrogenation, immunoreactivity with an anti-9 alpha, 11 beta-PGF2 antibody, and electron ionization mass spectral analysis, convincing evidence was obtained that these compounds in both stored and base-treated plasma were in fact PGF2 compounds. Formation of these compounds was found to occur by a nonenzymatic oxidative process in that the antioxidant, butylated hydroxytoluene, and the reducing agent, triphenylphosphine, markedly suppressed their formation. Evidence is presented to support a proposed mechanism that oxidative formation of these compounds involves the formation of endoperoxide intermediates which are directly reduced by naturally occurring biological substances to PGF2 compounds. Formation of these compounds occurs very readily in biological fluids. This finding has important ramifications not only for analysis of enzymatically derived PGF2 compounds but also for other eicosanoids which can be formed by this same nonenzymatic process. These analytical concerns apply to both immunoassay methods and physical methods of analysis such as gas chromatography/mass spectrometry.

Dinoprost↗
PubMed1990

NMR-studies of carcinogen reactions with DNA: ethylene dibromide and aflatoxin B1.

Two examples are described of the use of NMR spectroscopy to study the modification of DNA structure by carcinogens. The reaction of ethylene dibromide involves initial conjugation with glutathione, catalysed by glutathione S-transferase. Reaction of this adduct with DNA occurs at N7 of guanine. Through the use of stereospecifically 1,2-dideuteriated ethylene dibromide, the mechanism of reaction has been shown to involve an odd number, i.e. three, of SN2 inversions. Correlation spectra (COSY) were employed to analyse reaction stereochemistry. The relative configuration of the deuterium atoms in the products was initially assigned by 1H nuclear Overhauser effect (NOE) difference spectra and then confirmed by an independent synthesis of stereospecifically dideuteriated glutathione-guanine adducts. The second example involves reaction of the epoxide of aflatoxin B1 with DNA to form covalent adducts at N7 of guanine. Adduct formation was found to enhance duplex stability. Chemical shift changes for aflatoxin protons in the covalent adduct when compared with those for aflatoxin B1 non-covalently associated with DNA suggest that covalently linked aflatoxin is intercalated. NOEs confirm that the aflatoxin moiety is intercalated and show that it is on the 5' side of the guanine. This geometry leads to d(ATCGAT)2 forming an adduct in which only one chain has been modified by aflatoxin, while d(ATGCAT)2 forms a complex in which both chains have been modified.

Aflatoxin B1↗
PubMed1989

Oxidation of cycloalkylamines by cytochrome P-450. Mechanism-based inactivation, adduct formation, ring expansion, and nitrone formation.

Mechanism-based destruction of cytochrome P-450 (P-450) and P-450 heme is observed during the oxidation of N-cyclopropyl and N-cyclobutyl benzylamines. The slower inactivation by the cyclobutylamines relative to cyclopropylamines is consistent with known relative rates of ring opening of cycloalkyl-substituted aminium radicals. Evidence was found that porphyrin meso adducts of the type reported for horseradish peroxidase and cyclopropanone hydrate (Wiseman, J. S., Nichols, J. S., and Kolpak, M. X. (1982) J. Biol. Chem. 257, 6328-6332) were not formed. Radiolabels from cyclopropylamine substrates were covalently attached to protein but essentially only from the cyclopropyl portion and not the benzylic portion. Neither label appeared to be bound to extractable heme; however, during oxidations with cyclopropylamines, labeled P-450 heme became covalently attached to protein. Oxidation of 1-phenylcyclobutylamine by P-450 yielded 2-phenyl-1-pyrroline and 2-phenylpyrrolidine, and the ring expansion is interpreted as evidence for the existence of aminium radicals based on precedents with monoamine oxidase (Silverman, R. B., and Zieske, P. A. (1985) Biochemistry 24, 2128-2138). In addition, purified P-450PB-B oxidized N-(1-phenylcyclobutyl)-benzylamine to N-(1-phenyl)cyclobutyl phenyl nitrone, identified using spectral techniques. This transformation involves two sequential oxidations with either a hydroxylamine or benzylidene intermediate. While P-450 oxidized the amine to both compounds, only the hydroxylamine was rapidly oxidized to give the nitrone. The ring expansion and nitrone products are interpreted in the context of aminium radical intermediates involved in the mechanism of P-450-catalyzed amine oxidation.

Animals↗
PubMed1989

Carcinogen-nucleic acid interactions: equilibrium binding studies of aflatoxin B1 with the oligodeoxynucleotide d(ATGCAT)2 and with plasmid pBR322 support intercalative association with the B-DNA helix.

Equilibrium binding of aflatoxin B1 (AFB1) to the oligodeoxynucleotide d(ATGCAT)2 was examined by using 1H NMR. AFB1 binds to double-stranded d(ATGCAT)2 with an apparent binding constant of 3.7 x 10(3) M-1. The equilibrium is rapid on the NMR time scale; the observed 1H NMR spectrum represents the population-weighted average of the chemical shifts arising from the free and bound states of the oligodeoxynucleotide and the AFB1. The spectrum of d(ATGCAT)2 exhibits exchange broadening in the presence of AFB1, manifested as decreases in apparent T2 relaxation times for the d(ATGCAT)2 base protons. Upon binding to d(ATGCAT)2, the AFB1 signals are shifted upfield, indicative of increased shielding. The adenine H2 protons are also shifted upfield in the presence of the carcinogen. Small changes in chemical shift are observed for other d(ATGCAT)2 protons. A substantial decrease in the nonselective T1 relaxation time is observed for the adenine H2 protons in the presence of AFB1. Competition binding experiments in which the competing ligands actinomycin D, ethidium bromide, and spermidine were individually added to an AFB1-d(ATGCAT)2 equilibrium mixture showed that addition of 1 equiv of actinomycin D or 4 equiv of ethidium bromide was sufficient to displace bound AFB1 from d(ATGCAT)2. In contrast, the addition of spermidine did not result in the displacement of bound AFB1 molecules and may have slightly enhanced binding, presumably due to stabilization of the DNA duplex. 1H NOESY experiments confirmed that the overall conformation for the d(ATGCAT)2 duplex was right-handed both in the absence and in the presence of AFB1. Equilibrium binding of AFB1 to d(ATGCAT)2 is greatly diminished at higher temperatures at which the oligodeoxynucleotide is single-stranded.(ABSTRACT TRUNCATED AT 250 WORDS)

Aflatoxin B1↗
PubMed1989

Abdominal magnetic resonance imaging.

A review of the first five years of experience with pediatric abdominal Magnetic Resonance Imaging (MR) is presented. The abdomen is examined organ by organ with description of normal anatomy and pathological processes. Practical clinical uses of MR are indicated. There is a brief review of motion artifact suppression techniques.

Abdomen↗
PubMed1988

Non-Watson-Crick structures in oligodeoxynucleotides: self-association of d(TpCpGpA) stabilized at acidic pH.

The 1H NMR spectrum of the tetradeoxynucleotide d(TpCpGpA) was examined as a function of temperature, pH, and concentration. At pH 7 and above the solution conformation for this oligodeoxynucleotide appears to be a mixture of random coil and Watson-Crick duplex. At 25 degrees C, a pH titration of d(TpCpGpA) shows that distinct conformational changes occur as the pH is lowered below 7.0. These conformational changes are reversible upon readjusting the pH to neutrality, indicating the presence of a pH-dependent set of conformational equilibria. At 25 degrees C, the various conformational states in the mixture are in rapid exchange on the NMR time scale. Examination of the titration curve shows the presence of distinct conformational states at pH greater than 7, and between pH 4 and pH 5. At pH less than 4, a third conformational state is present. When the pH titration is repeated at 5 degrees C, the conformational equilibria are in slow exchange on the NMR time scale; distinct signals from each conformational state are observable. The stable conformational state present between pH 4 and pH 5 represents an ordered conformation of d(TpCpGpA) which dissociates to a less ordered structure upon raising the temperature. This ordered conformation does not result from an intramolecular rearrangement, as is shown by by spectra obtained by varying oligodeoxynucleotide concentration at constant pH. The ordered conformation differs from the Watson-Crick helix, as is shown from nuclear Overhauser enhancement experiments, as well as chemical shift data. An ordered conformation for d(TpCpGpA) was previously reported [Reid, D. G., Salisbury, S. A., Brown, T., & Williams, D. H. (1985) Biochemistry 24, 4325-4332].(ABSTRACT TRUNCATED AT 250 WORDS)

Hydrogen-Ion Concentration↗
PubMed1988

Absolute configuration of cis-12-oxophytodienoic acid of flaxseed: implications for the mechanism of biosynthesis from the 13(S)-hydroperoxide of linolenic acid.

cis-12-Oxophytodienoic acid (cis-12-oxo-PDA) is a C18 cyclopentenone formed from the 13-(S)-hydroperoxide of linolenic acid in flaxseed and other plant tissues. Although the structure of cis-12-oxo-PDA is well established, the absolute configuration of the side chains has not been determined. We have now measured this important parameter by two independent approaches. The CD spectrum of freshly prepared cis-12-oxo-PDA showed no deviations from base line--implying that the product is racemic. This conclusion was checked by a high-pressure liquid chromatography (HPLC) method capable of resolving the enantiomers; cis-12-oxo-PDA was reduced to two saturated hydroxy analogues which were each converted to (-)-menthoxycarbonyl diastereomers and analyzed by HPLC. Each epimer was resolved as two peaks of equal area, thus confirming that their cis-12-oxo-PDA parent is a racemic mixture, enantiomeric at the ring junctures. We propose that the biosynthesis of racemic cis-12-oxo-PDA proceeds by dehydration of the 13(S)-hydroperoxide to an allene oxide. A major fate of the allene oxide is hydrolysis to an alpha-ketol, which is always formed together with cis-12-oxo-PDA. The allene oxide also opens to a zwitterion, which undergoes charge delocalization to form a planar intermediate; this structure is the achiral precursor of the stable end product of pericyclic ring closure, viz., racemic cis-12-oxo-PDA.

Chromatography, High Pressure Liquid↗
PubMed1988

Selective reversible deuteriation of oligodeoxynucleotides: simplification of two-dimensional nuclear Overhauser effect NMR spectral assignment of a non-self-complementary dodecamer duplex.

Oligodeoxynucleotides are reversibly deuteriated at the purine C8 and cytosine C5 positions with deuterioammonium bisulfite at pD 7.8. The exchange reaction is complete after 48 h at 65 degrees C. When an oligomer deuteriated under these conditions is analyzed by 1H nuclear magnetic resonance (NMR) spectroscopy, the purine H8 and cytosine H5 proton signals are selectively removed from the spectrum. A non-self-complementary oligodeoxynucleotide that has been deuteriated in this manner may be annealed with its complement and the resulting heteroduplex analyzed by two-dimensional nuclear Overhauser enhancement (NOESY) spectroscopy. NOE cross-peaks arising from pyrimidine H6-deoxyribose H1' dipolar interactions in both strands are observed, but purine H8-deoxyribose H1' and purine H8-deoxyribose H2',H2" dipolar interactions are only observed for the nondeuteriated strand. The intense cytosine H5-H6 cross-peaks are also removed from the spectrum of the deuteriated strand, which further simplifies interpretation since these strong cross-peaks often interfere with less intense NOE cross-peaks arising from dipolar coupling between purine H8 or pyrimidine H6 and deoxyribose anomeric protons. The resulting spectral simplification allows unambiguous assignments to be made on NOEs that otherwise may be difficult to distinguish. The deuteration procedure is demonstrated with the sequence d(CGTTATAATGCG).d(CGCATTATAACG), which has previously been assigned by traditional NOESY methods [Wemmer, D. E., Chou, S.-H., Hare, D. R., & Reid, B. R. (1984) Biochemistry 23, 2262-2268]. Although the assignment of this dodecadeoxynucleotide may be completed without deuteriation, several NOEs must be assigned indirectly because of degeneracies in the chemical shift of the purine H8 protons.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Composition↗
PubMed1988

Isolation and characterization of natural allene oxides: unstable intermediates in the metabolism of lipid hydroperoxides.

Allene oxides are unstable epoxides that have been implicated as intermediates in the biotransformation of hydroperoxyicosatetraenoic acids and related hydroperoxides to ketols and cyclopentenones. Direct proof of the structure of the putative allene oxide intermediates has been hampered by their extreme instability under the conditions of their biosynthesis (t1/2 approximately 15-30 sec at 0 degree C and pH 7.4). We now report the isolation and structural elucidation of allene oxides prepared from the (13S)-hydroperoxides of linoleic and linolenic acids. The compounds were biosynthesized by using a very active enzyme preparation from flaxseed. After a 5-sec incubation at 0 degrees C, the allene oxide metabolites were extracted and purified as the methyl ester derivatives at -15 degrees C. The structures were established by UV, CD, NMR, and oxygen-18 labeling experiments. 12,13(S)-Oxido-9Z,11-octadecadienoic acid is derived from linoleic acid, and 12,13(S)-oxido-9Z,11,15Z-octadecatrienoic acid is from linolenic acid. Analysis of the breakdown products formed on exposure to water led to identification of hydrolysis and cyclization products previously characterized as enzymic derivatives of the (13S)-hydroperoxides in flaxseed. Our results give direct proof of the structure of the allene oxide intermediates and should facilitate further investigation of the metabolism of this class of epoxide to prostaglandins, clavulones, and other stable end products.

Alkadienes↗