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K F Faull

Publications and source records attributed to K F Faull.

132 records · Page 8Linked to original sources
PubMed1969

Nitrite oxidase and nitrate reductase in Nitrobacter agilis.

Nitrite oxidase and nitrate reductase in Nitrobacter agilis were shown to be separate enzymes. The best separation of the two systems was achieved by ammonium sulphate fractionation. The effects of various compounds, including antimycin A, 2-n-heptyl-4-hydroxyquinoline N-oxide and chlorate, also clearly distinguish between the two enzyme reactions. The relationship between the two opposing reactions in Nitrobacter is discussed.

Antimycin A↗
PubMedDate not supplied

Characterization of endorphins from the pituitary of the spiny dogfish Squalus acanthias.

Opioid-like immunoreactive material was extracted from the pituitary and brain of the Spiny Dogfish Shark Squalus acanthias. The immunoreactive material in the pituitary extracts was purified to apparent homogeneity by reverse phase high performance liquid chromatography and subsequently characterized by amino acid analysis, Edman degradation and fast atom bombardment mass spectrometry. The largest opioid-like peptide isolated contained 30 amino acids and showed 80 percent homology with salmon endorphin-II but less than 50 percent homology with human beta-endorphin. Three structural variants of this molecule were also characterized. These variants were shown to be shorter N-terminal fragments, two of which corresponded to cleavage products at the single basic residues arginine and lysine. Cleavage at a single lysine residue has not been reported for posttranslational processing of beta-endorphin in mammals and could represent a modification seen only in lower vertebrates. The remaining fragment corresponded to a loss of 3 residues from the C-terminus of the parent molecule. No alpha-N-acetylated peptides were detected. These results provide the first unequivocal confirmation of beta-endorphin in an elasmobranch and provide evidence of novel N-terminal variants of beta-endorphin.

Acetylation↗
PubMedDate not supplied

Harman in rat brain, lung and human CSF: effect of alcohol consumption.

A simple, sensitive, HPLC method for the determination of harman has been developed and used to quantitate harman in rat brain (0.41 +/- 0.05 ng/g, n = 7) and rat lung (1.88 +/- 0.55 ng/g, n = 6). The definitive identification of harman in these tissues was accomplished by derivatizing the beta-carboline with pentafluorobenzyl bromide and using gas chromatography-electron capture chemical ionization mass spectrometry. Rats treated acutely with ethanol or subchronically with ethanol in the presence or absence of disulfiram did not have altered harman concentrations. Analysis of control human CSF samples and CSF samples taken from alcoholic patients (n = 8) at the time of intoxicated admission and one week later indicated a predominant absence of harman. These data suggest that harman is unlikely to be formed as a result of ethanol ingestion; its origin and pharmacological significance remain to be determined.

Alcohol Drinking↗
PubMedDate not supplied

Synthesis of the skeleton of the morphine molecule by mammalian liver.

The possibility that morphine could be synthesized in animals has long been considered and a pathway in mammalian brain analogous to that in the opium poppy has been proposed. Substances have been detected in mammalian brain that are recognized by antisera raised against morphine. Recently we reported the presence of three such immunoreactive substances in bovine hypothalamus and adrenal, and in rat brain, and the definitive identification of two of them by gas chromatography-mass spectrometry as morphine and codeine. Incorporation of a labelled precursor has demonstrated the biosynthesis of morphine in the opium poppy from tyrosine-derived units (see Fig. 1). Intramolecular coupling of reticuline to form salutaridine is the critical step that generates the morphine skeleton (morphinan) and the stereochemistry of the morphinan series. We now report the conversion in vivo and in vitro of reticuline to salutaridine by rat liver, but this conversion is not detectable in rat brain and bovine adrenal. This is the first direct demonstration of the synthesis of a morphinan in an animal tissue and also supports the hypothesis that morphine and codeine in brain and adrenal are of endogenous origin.

Adrenal Glands↗
PubMedDate not supplied

Synthesis, secondary structure and folding of the bend region of lung surfactant protein B.

Previous theoretical analysis of the primary structure of lung surfactant protein SP-B indicates a disulfide-linked, hydrophobic midsequence that forms a hairpin-like motif. Here, we experimentally investigate the secondary structure of the disulfide-stabilized bend region by synthesizing two 12-residue analogs of the SP-B midsequence. The native peptide has the same sequence for residues 35 to 46 as native human SP-B, while, in the second mimic peptide, Leu40 and Val41 were replaced with D-Ser and L-His. Both peptides contain cysteine residues at the N- and C-terminus (Cys35 and Cys46, respectively). Oxidation/reduction experiments with fast atom bombardment mass spectrometry showed mass shifts of approximately 2 daltons, consistent with the oxidized peptides existing in solution as monomers, each with one internal disulfide bond (Cys35-Cys46). Since circular dichroism and Fourier-transform infrared measurements show that both peptides assume turn conformations in structure-promoting solvents such as trifluoroethanol (TFE), a structural model is proposed in which Cys35 and Cys46 are brought in close apposition through an internal bend in the peptide. Consistent with this model are electron spin resonance (ESR) results of the mimic peptide nitroxide spin-labeled at Cys35 and Cys46. For the double spin-labeled mimic peptide in TFE. ESR spectra indicated broadening characteristic of either radical interactions or decreased mobility, or both. Increases in radical interactions for the double spin-labeled mimic peptide would be expected for Cys35 and Cys46 approaching within 14 A in structure-promoting solvents, while decreases in spin-label mobility could be due to the formation of a loop. Based on these observations with peptide analogs, residues 35 to 46 probably form a similar bend in the full-length protein.

Amino Acid Sequence↗