Previously, we showed that immunoglobulin G (IgG) Fc fragments can expose neoepitopes specific to antibodies that were named regulatory rheumatoid factor (regRF). RegRF confers resistance to experimental autoimmune diseases. Immunization of rats with rat Fc fragments exposing neoepitopes recognized by regRF reduces the symptoms of collagen‐induced arthritis. Therefore, IgG Fc fragments that expose neoepitopes recognized by regRF are promising antirheumatic agents and regRF‐producing lymphocytes are potential therapeutic biotargets. The purpose of this study was to elucidate the physicochemical features of human IgG Fc fragments that are associated with the presence of immunosuppressive neoepitopes recognized by regRF. It was found that the acquisition of neoepitopes recognized by regRF is associated with a reduction of the hinge disulfide bonds and conformational changes in the Fc fragment domains. Alkylation of thiol groups in the hinge leads to loss of the epitopes. Therefore, the neoepitopes recognized by regRF may form directly in the hinge when interchain disulfide bonds are reduced or in the region of the CH2 domain as part of the conformational changes caused by the reduction of the interchain disulfide bonds in the hinge. Species‐specificity studies of neoepitopes recognized by regRF revealed that human and rat neoepitopes recognized by regRF are cross‐reactive.

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Caramelized carbohydrate's products contain ester functions, which are play a significant role in foodstuff properties, but their formation processes are not considered in detail [1]. In present work sugar lactone's fragments in monosaccharide's thermodestruction products structure were identified using FTIR spectroscopy, several characteristic bands were choosing for structural analysis. The bands at 1164 and 1255 cm -1 are symmetric and asymmetric stretching vibrations of the -C(=O)-O-C-group respectively. Complex signal with maxima near 1720 cm -1 , assigned to C=O stretching vibrations, was resolved using derivative procedures (Figure 1).

The results of studies of the sorption of carbohydrate caramels from aqueous solutions by highly dispersed adsorbents - carbonization products synthesized in the D-glucose - p-toluidine system are presented. Based on the analysis of the structural features of the adsorbent and the adsorbate with the use of infrared Fourier spectroscopy data, the physical nature of the interaction of the caramel components with the surface is mainly shown. Meanwhile binding probably occurs due to polar groups of carbonyl nature. An analysis of the difference spectra in the region of 1500-1740 cm−1 allows detailing the examination and confirming the nature of the sorption interaction. The research results are promising in the development of methods for the synthesis of carbon-saturated products, sorption-active with respect to substances of carbohydrate nature, which is of interest for food and pharmaceutical industries.

The aim of the study was to investigate the processes of formation and structural group composition of the products formed during the reaction of D-glucose with p-toluidine in anhydrous ethanol using electronic and vibrational spectroscopy methods. The evolution of the profiles of the electronic spectra of working solutions shows the formation of a chromophore system: clear peaks at 380 and 440 nm are already present at a reaction time of 60 min. The appearance of an additional maximum at 520 nm (90, 120 min) likely corresponds to the formation of chromophores in condensed structures, as confirmed by a decrease in the values of the E 4 /Е 6 indices over time. The dynamics of the transformation of structural elements is also clearly seen in the analysis of IR spectra: as the reactions proceed, the CH aliphatic component of the structure decreases, while the aromatisation and functionalisation of products by chromophore groups increases. For products obtained between 90 and 120 min, a clear band at 1656 cm -1 , attributed to stretching vibrations of multiple bonds in conjugated C=C-C=O systems and azomethine fragments, indicates the of condensation reactions. In the spectra of insoluble solid products fractionated by water, the intensity of the bands at 1656 and 1190 cm-1 is significantly reduced; this is possibly due to the transfer of some of the coloured low molecular weight products to the aqueous phase. A comparison of the IR Fourier transform spectra of the final solid products with the spectra of natural and synthetic humic-like substances indicates their similar structural group composition. The intensity of the bands at 1620, 1508 and 815 cm -1 indicates a significant contribution of the aromatic component to the structure of the products of water-insoluble fractions; the water-soluble fractions mainly include aliphatic oxygen-containing structures resulting from the oxidative destruction of the initial carbohydrate. The synthesised products seem promising as convenient plant growth regulators with controlled release of the active substance.