A collection of N‐triazinylammonium sulfonates, designed according to the concept of “superactive esters”, was obtained by treatment of ammonium sulfonates with 2‐chloro‐4,6‐dimethoxy‐1,3,5‐triazine. The structure of the tertiary amine as well as sulfonate anion influenced their reactivity and stability in N,N‐dimethylformamide (DMF) solution. The reagents were successfully used in solution‐ and solid‐phase synthesis of Z‐, Boc‐, and Fmoc‐protected peptides containing natural and unnatural sterically hindered amino acids as well as in [2+1] fragment condensation approaches, yielding the final products in 80–100 % yield and high optical purity. In manual SPPS of the [Aib]2[Aib]4‐enkephalin analogue and the ACP(65–74) peptide fragment VQAAIDYINEG, several sulfonates yielded peptides significantly faster than TBTU or HATU. Comparative analyses demonstrated that 4‐(4,6‐dimethoxy‐1,3,5‐triazin‐2‐yl)‐4‐methylmorpholinium 4‐toluenesulfonate was the most versatile reagent in a wide range of coupling procedures.
Overlapping decapeptide fragments of H. pylori urease subunit A (UreA) were synthesized and tested with polyclonal antibodies against Canavalia ensiformis (Jack bean) urease. The linear epitopes of UreA identified using the dot blot method were then examined using epitope mapping. For this purpose, series of overlapping fragments of UreA, frameshifted AE four amino acid residues were synthesized. Most of the UreA epitopes which reacted with the Jack bean urease polyclonal antibodies had been recognized in previous studies by monoclonal antibodies against H. pylori urease. Fragments 11 -24, 21 -33, and 31 -42 were able to interact with the Jack bean urease antibodies, giving stable immunological complexes. However, the lack of recognition by these antibodies of all the components in the peptide map strongly suggests that a non-continuous (nonlinear) epitope is located on the N-terminal domain of UreA.
Lysozyme (1,4-β-N-acetylmuramidase) is commonly applied in the food, medical, and pharmaceutical industries. In this study, we tested a novel application of fluorescein-modified lysozyme (using carboxyfluorescein with a triazine-based coupling reagent) as a new tool for the detection of Gram-positive soil bacteria. The results, obtained by cultivation methods, fluorescence analysis, and laser interferometry, showed that, after optimization, fluorescein-modified lysozyme could be used to evaluate the prevalence of Gram-positive bacteria essential in bioremediation of soils with low pH, such as those degraded by sulfur.
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