engleski

Electrochemical and immunochemical study of polysaccharide-protein molecular interactions

Polysaccharide (PS)-protein interactions have been investigated in various scientific fields such as life science, food science, oceanology, etc. Proteins and some of the PSs, depending on the structure and composition, produce catalytic hydrogen evolution reaction (CHER) peak in a buffer solution observable by electrochemical methods at Hg electrodes. In alternating current voltammetry (ACV, out of phase mode) catalytically active PSs and proteins strongly adsorbed on the mercury electrode inducing a decrease of capacitive current below the background electrolyte at around -1.8 V (“tensammetric minimum”), while using ACV in phase mode a CHER peak was observed. Tensammetric minimum of BSA and Concanavalin A (ConA, proteins) and chitosan (PS) were negligibly disturbed in an excess of catalytically inactive PS dextran (DX), meaning that both unspecific (chitosan-DX, BSA-DX) and specific (ConA-DX) interactions in solution were not strong enough to alter electrochemical effects observed in the solution of BSA, ConA and chitosan alone. Potential, ionic strength, temperature, and current density affect protein structural transition at the electrode surface. Stability of surface-attached protein exposed to negative potentials for ms time intervals depends on different stripping current (Istr): at higher negative Istr the BSA protein is in native form while applying lower negative Istr BSA denatures. Using adsorptive transfer procedure, we show here that BSA could be stable at negative potentials even at lower negative Istr if BSA-alginate interactions on the electrode occur. Such behaviour depended on ionic strength and alginate concentration (no published). Glycosylation of proteins plays an important role in health and diseases. We developed a monoclonal antibody Manost 2.1 in mice after immunization with the adduct of mannan with Os(VI)temed complex (temed is N, N, N′, N′-tetramethylethylenediamine) and tested its specific interaction with biomolecules treated with Os(VI)temed using dot blot immunoassay. Manost 2.1 showed specificity toward Os(VI)temed-modified PSs, glycoproteins and ribonucleotide at the 3’-end in DNA, while no interactions with unmodified compounds nor non-glycosylated proteins treated with Os(VI)temed were observed, suggesting that modified glycan, either alone or bound in the glycoproteins is crucial for interaction with the antibody.

Polysaccharides ; proteins ; interactions

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