24753-52-4Relevant academic research and scientific papers
Visible light-induced oxidation of unsaturated components of cutins: A significant process during the senescence of higher plants
Rontani, Jean-Francois,Rabourdin, Adelaide,Pinot, Franck,Kandel, Sylvie,Aubert, Claude
, p. 313 - 321 (2005)
9-Hydroperoxy-18-hydroxyoctadec-10(trans)-enoic and 10-hydroperoxy-18- hydroxyoctadec-8(trans)-enoic acids deriving from type II (i.e. involving 1O2) photooxidation of 18-hydroxyoleic acid were detected after visible light-induced senescence experiments carried out with Petroselinum sativum and subsequent cutin depolymerisation. These results showed that in senescent plants, where the 1O2 formation rate exceeds the quenching capacity of the photoprotective system, 1O2 can migrate outside the chloroplasts and affect the unsaturated components of cutins. Significant amounts of 9,18-dihydroxyoctadec-10(trans)-enoic and 10,18-dihydroxyoctadec-8(trans)-enoic acids resulting from the reduction of these photoproducts of 18-hydroxyoleic acid were also detected in different natural samples. These results well support the significance of the photooxidation of the unsaturated components of higher plant cutins in the natural environment.
Human cytochrome P450 4F11: Heterologous expression in bacteria, purification, and characterization of catalytic function
Tang, Zhongmei,Salamanca-Pinzon, Sandra Giovanna,Wu, Zhong-Liu,Xiao, Yi,Guengerich, F. Peter
, p. 86 - 93 (2010)
Human cytochrome P450 (P450) 4F11 is still considered an "orphan" because its function is not well characterized. A bacterial expression system was developed for human P450 4F11, producing ～230 nmol P450 from a 3-l culture of Escherichia coli. P450 4F11 was purified and utilized for untargeted substrate searches in human liver extract using a liquid chromatography/mass spectrometry-based metabolomic and isotopic labeling approach (Tang et al., 2009 [19]). Four fatty acids-palmitic, oleic, arachidonic, and docosahexaenoic-were identified in human liver and verified as substrates of P450 4F11. The products were characterized as ω-hydroxylated fatty acids by gas chromatography-mass spectrometry analysis of their trimethylsilyl derivatives. Kinetic analysis of the oxidation products confirmed that the fatty acids are substrates oxidized by P450 4F11. P450 4F11 also exhibited low activity for some drug N-demethylation reactions but none for activation of several pro-carcinogens.
Stereochemistry of C18 monounsaturated cork suberin acids determined by spectroscopic techniques including 1H-NMR multiplet analysis of olefinic protons
Santos, Sara,Gra?a, José
, p. 192 - 200 (2014/05/06)
Introduction Suberin is a biopolyester responsible for the protection of secondary plant tissues, and yet its molecular structure remains unknown. The C18:1 ω-hydroxyacid and the C18:1 α,ω-diacid are major monomers in the suberin structure, but the configuration of the double bond remains to be elucidated. Objective To unequivocally define the configuration of the C18:1 suberin acids. Methods Pure C18:1 ω-hydroxyacid and C18:1 α,ω-diacid, isolated from cork suberin, and two structurally very close C18:1 model compounds of known stereochemistry, methyl oleate and methyl elaidate, were analysed by NMR spectroscopy, Fourier transform infrared (FTIR) and Raman spectroscopy, and GC-MS. Results The GC-MS analysis showed that both acids were present in cork suberin as only one geometric isomer. The analysis of dimethyloxazoline (DMOX) and picolinyl derivatives proved the double bond position to be at C-9. The FTIR spectra were concordant with a cis-configuration for both suberin acids, but their unambiguous stereochemical assignment came from the NMR analysis: (i) the chemical shifts of the allylic 13C carbons were shielded comparatively to the trans model compound, and (ii) the complex multiplets of the olefinic protons could be simulated only with 3JHH and long-range 4JHH coupling constants typical of a cis geometry. Conclusion The two C18:1 suberin acids in cork are (Z)-18-hydroxyoctadec-9-enoic acid and (Z)-octadec-9-enedoic acid. Copyright 2013 John Wiley & Sons, Ltd. The two C18:1 cork suberin ω-hydroxyacid and α,ω-diacid were proved to have a cis configuration: (Z)-18-hydroxyoctadec-9-enoic acid and (Z)-octadec-9-enedoic acid. Their double bond stereochemistry was elucidated by spectroscopic techniques, namely 1H-NMR and 13C-NMR. The chemical shifts of the olefinic and allylic protons and of the allylic carbons were diagnostic, and the 1H-NMR multiplets of the olefinic protons could only be simulated using 3JHH and long-range 4J HH coupling constants typical of the cis configuration. The revealed stereochemistry of this two major suberin monomers brings a new insight into the mostly unknown suberin macromolecular structure. Copyright
