Hydroxylated Derivative (hydroxylated + derivative)

Distribution by Scientific Domains


Selected Abstracts


High-performance liquid chromatography/electrospray ionization tandem mass spectrometry of hydroxylated uroporphyrin and urochlorin derivatives formed by photochemical oxidation of uroporphyrinogen I

BIOMEDICAL CHROMATOGRAPHY, Issue 5 2007
Malcolm Danton
Abstract Hydroxylated uroporphyrin I and urochlorin I derivatives formed by photochemical oxidation of uroporphyrinogen I were separated by high-performance liquid chromatography and fully characterized by electrospray ionization tandem mass spectrometry. The porphyrins and chlorins were identified by analysis of their product ion spectra with each hydroxylated derivative giving a characteristic collision-induced dissociation fragmentation pattern. The porphyrins and chlorins characterized were meso -hydroxyuroporphyrin I, , -hydroxypropionic acid uroporphyrin I, , -hydroxypropionic acid uroporphyrin I, hydroxyacetic acid uroporphyrin I, trans- 7-hydroxy-8-spirolactoneurochlorin I, cis- 7-hydroxy-8-spirolactoneurochlorin I and trans- and cis- 7,8-dihydroxyurochlorins I. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Dissection of the Late Steps in Aureothin Biosynthesis

CHEMBIOCHEM, Issue 1 2006
Markus Müller
Part of the queue. Biosynthesis of the cytostatic polyketide aureothin (1) in Streptomyces thioluteus was found to involve two tailoring steps (see scheme). Mutational biosynthesis of nor -deoxyaureothin (,- 2) and a hydroxylated derivative (3), together with biotransformation experiments revealed a well-defined order for the polyketide-tailoring steps. Regioselective ,-pyrone methylation was found to be the penultimate biosynthetic step prior to furan-ring formation. [source]


Importance of hydrogen-bonding sites in the chiral recognition mechanism between racemic D3 terbium(III) complexes and amino acids

CHIRALITY, Issue 5 2009
Ahmed Moussa
Abstract The perturbation of the racemic equilibrium of luminescent D3 terbium(III) complexes with chelidamic acid (CDA), a hydroxylated derivative of 2,6-pyridine-dicarboxylic acid (DPA), by added chiral biomolecules such as L -amino acids has been studied using circularly polarized luminescence and 13C NMR spectroscopy. It is shown in this work that the chiral-induced equilibrium shift of [Tb(CDA)3]6, by L -amino acids (i.e. L -proline or L -arginine) was largely influenced by the hydrogen-bonding networks formed between the ligand interface of racemic [Tb(CDA)3]6, and these added chiral agents. The capping of potential hydrogen-bonding sites by acetylation in L -proline led to a ,100-fold drop in the induced optical activity of the [Tb(CDA)3]6,:N -acetyl- L -proline system. This result suggested that the hydrogen-bonding networks serve as the basis for further noncovalent discriminatory interactions between racemic [Tb(CDA)3]6, and added L -amino acids. Chirality, 2009. © 2008 Wiley-Liss, Inc. [source]


Structural determination of two new triterpenoids biotransformed from glycyrrhetinic acid by Mucor polymorphosporus

MAGNETIC RESONANCE IN CHEMISTRY, Issue 2 2010
Xiu Lan Xin
Abstract Five hydroxylated derivatives of glycyrrhetinic acid by Mucor polymorphosporus were isolated. Among them, 6,, 7,-dihydroxyglycyrrhentic acid (2) and 27-hydroxyglycyrrhentic acid (3) are new compounds. Their chemical structures were identified by spectral methods including 2D-NMR. Copyright © 2009 John Wiley & Sons, Ltd. [source]


A novel approach for identification and measurement of hemoglobin adducts with 1,2,3,4-diepoxybutane by liquid chromatography/electrospray ionisation mass spectrometry and matrix-assisted laser desorption/ionisation tandem mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 8 2001
Adriana Basile
The structural characterisation of the adducts formed by in vitro interaction of hemoglobin (Hb) with 1,2,3,4-diepoxybutane (DEB), the most reactive 1,3-butadiene (BD) metabolite, was obtained by liquid chromatography/electrospray ionisation mass spectrometry (LC/ES-MS) analysis of modified tryptic peptides of human hemoglobin chains. The reactive sites of human hemoglobin towards DEB and its hydroxylated derivatives (trihydroxybutyl (THB)-derivatives) were identified through the characterisation of alkylated tryptic peptides by matrix-assisted laser desorption/ionisation tandem mass spectrometry (MALDI-MS/MS). Based on this characterisation, a procedure was set up to measure the Hb-adducts of THB-derivatives by isotope dilution mass spectrometry with the use of a deuterated peptide standard. The results obtained here could permit optimisation of molecular dosimetry of BD-adducts, and extension of the analysis to the biological monitoring of occupational exposure to butadiene. Copyright © 2001 John Wiley & Sons, Ltd. [source]