Search results for "Fast atom bombardment"
showing 5 items of 25 documents
Structure elucidation of the adducts formed by fjord region Dibenzo[a,l]pyrene-11,12-dihydrodiol 13,14-epoxides with deoxyguanosine.
1999
Model adducts to be used in the identification of biologically formed adducts were synthesized by reaction of fjord-region dibenzo[a,l]pyrene 11,12-dihydrodiol 13,14-epoxides (DB[a,l]PDE) and deoxyadenosine (dA). The (+/-)-anti-DB[a,l]PDE was reacted with dA in dimethylformamide at 100 degrees C for 30 min to give four DB[a, l]PDE-14-N(6)dA adducts: (-)-anti-trans (26%), (+)-anti-trans (26%), (-)-anti-cis (17%), and (+)-anti-cis (17%). The (+/-)-syn-DB[a,l]PDE was reacted with dA under the same conditions to yield four DB[a, l]PDE-14-N(6)dA adducts and one N7Ade adduct: (+)-syn-cis (19%), (+)-syn-trans (13%), (-)-syn-cis (19%), (-)-syn-trans (13%), and (+/-)-syn-DB[a,l]PDE-14-N7Ade (22%). T…
Isolation and structural characterization of polypeptide antibiotics of the peptaibol class by high-performance liquid chromatography with field deso…
1984
Abstract A number of polypeptide antibiotics of the peptaibol class, i.e., trichotoxin, alamethicin, suzukacillin, hypelcin and paracelsin, have been separated into components and isolated by high-performance liquid chromatography on spherical, porous octadecylsilyl bonded phases. All peptaibols were found to reveal a strong microheterogeneity due to single or multiple amino acid exchange. Most of the closely related and partially isobaric sequence analogue could be resolved using mixed alcohol—water eluents. As demonstrated by the structure analysis of the paracelsins and the main component of trichotoxin A-50, high-performance liquid chromatography with field desorption and fast atom bomb…
Chromatographic and mass spectrometric characterization of the structures of the polypeptide antibiotics samarosporin and stilbellin and identity wit…
1983
The structural identity of the polypeptide antibiotics, samarosporin I(II) and stilbellin I(II) with emerimicin IV(III) has been established by thin-layer chromatography, quantitative amino acid analysis by ion-exchange chromatography, gas-liquid chromatography of the N-pentafluoropropionyl amino acid n-propyl esters and N,O-bis-pentafluoropropionyl phenylalaninol with quartz capillaries coated with the chiral stationary phase N-propionyl-L-valine-tert-butylamide, and determination of the relative molecular masses and sequence-specific fragments by field desorption fast atom bombardment mass spectrometry. The separation of closely related sequence analogues of the above polypeptides could b…
Conjugation reactions of polyaromatic quinones to mono- and bisglutathionyl adducts: Direct analysis by fast atom bombardment mass spectrometry
1988
The conjugation products of several reactive quinones with glutathione have been identified by fast atom bombardment mass spectrometry. Appropriate conditions have been developed which enabled the direct, dynamic mass spectral analysis of spontaneous, as well as glutathione transferase catalysed conjugation reactions. Applications to a series of quinones provided the direct detection and differentiation of the formation of mono- and bisglutathionyl adducts between regioisomeric quinone substrates in that only 1,4-quinones yielded bisglutathionyl adducts, which were not observed for the 1,2-isomers.
Elucidation of structure and microheterogeneity of the polypeptide antibiotics paracelsin and trichotoxin A-50 by fast atom bombardment mass spectrom…
1984
Specific and sensitive procedures have been developed which enabled the structure elucidation of the polypeptide antibiotics (peptaibols), paracelsin isolated from Trichoderma reesei, and of trichotoxin A-50 from Trichoderma viride, by fast atom bombardment and field desorption mass spectrometry. Both peptides were found to exhibit a pronounced microheterogeneity by single and multiple exchange of amino acids. Separation by analytical and semipreparative high-performance liquid chromatography (HPLC) on octadecylsilyl-bonded, reversed-phase columns afforded a series of sequence analogues for each polypeptide. Unequivocal molecular weight and sequence identifications were obtained by positive…