منابع مشابه
Quaternary amine-induced peptide degradation via cyclization.
In this study, we investigated intramolecular cyclizations in peptides containing quaternary amines. Two types of cyclization reactions are studied: (a) those involving a trimethylammonium butyric acid (TMAB) charge tag and (b) those involving trimethylated lysine. Both types of reactions result in the release of trimethylamine via an S(N)2 mechanism involving a lone pair of electrons on the ox...
متن کاملCyclization of acylium ions with nitriles: gas-phase synthesis and characterization of 1,3,5-oxadiazinium ions
Gas phase reactions of mass-selected acylium ions [CH3–C ¢O (1), CH2¢CH–C ¢O (2), C6H5–C ¢O (3), and (CH3)2N–C ¢O (4)] with nitriles (CH3CN, C2H5CN, CH2¢CHCN, and C6H5CN) were investigated using pentaquadrupole multiple-stage mass spectrometry. In analogy with the solution behavior, the ions were found to react readily with benzonitrile by cyclization via double nitrile addition to form aromati...
متن کاملGenerality of peptide cyclization catalyzed by isolated thioesterase domains of nonribosomal peptide synthetases.
The C-terminal thioesterase (TE) domains from nonribosomal peptide synthetases (NRPSs) catalyze the final step in the biosynthesis of diverse biologically active molecules. In many systems, the thioesterase domain is involved in macrocyclization of a linear precursor presented as an acyl-S-enzyme intermediate. The excised thioesterase domain from the tyrocidine NRPS has been shown to catalyze t...
متن کاملThe Cyclization of Natural Rubber
The effects of solvent, temperature, time, weight percent of catalyst on the rate and mechanism of cyclization of natural rubber (NR) was studied in toluene and xylene solutions having tin tetra chloride catalyst (SnCl4). Iodometric titration show, with 8% SnCl4 (based on polymer weight) cyclization occurs, leaving 27.4% of the total unsaturation. Infrared spectra of c...
متن کاملImmobilization of Staphylococcus aureus Sortase A on Chitosan Particles and Its Applications in Peptide-to-Peptide Ligation and Peptide Cyclization.
Chitosan macro-particles prepared by the neutralization method were applied to Sortase A (SrtA) immobilization using glutaraldehyde as a crosslinking agent. The particles were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Response surface methodology (RSM) was employed to optimize the immobilization process. An average specific activity ...
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ژورنال
عنوان ژورنال: Journal of the American Society for Mass Spectrometry
سال: 2009
ISSN: 1044-0305,1879-1123
DOI: 10.1016/j.jasms.2009.08.013