Effects of stewing with tea polyphenol on the gel properties, microstructure, and secondary structure of boiled egg white.

This study aimed to investigatethe mechanism of stewing with tea polyphenols (TP) on the properties of boiled egg white gel (BEWG). The results indicated that, during the stewing process, soluble protein and hardness showed an overall increasing trend, while surface hydrophobicity showed a decreasing trend with blue-shift. The free sulfhydryl group showed that TP could promote the formation of disulfide bonds, and the position of immobilized water at T2 showed a decreasing trend. Environmental scanning electron microscopy and SDS-PAGE showed that the protein gel aggregation degree increased. Moreover, Fourier transform infrared spectrometry showed that protein polarity increased and that α-helices, ß-turn, intramolecular ß-sheets, as well as intermolecular antiparallel ß-sheets showed an increasing trend. Generally, TP strengthened protein aggregation by promoting the formation of disulfide and hydrogen bonds, thus enhancing the gel strength of BEWG. Moreover, the secondary structure of proteins became more stable under the action of TP, and the higher the concentration of TP, the greater the effect on BEWG. PRACTICAL APPLICATION: TP, an ideal, cheap, and safe natural food additive, can be applied to the processing of egg products because the addition of TP can significantly improve the gel strength of egg white.

Novel 1,3,4-Selenadiazole-Containing Kidney-Type Glutaminase Inhibitors Showed Improved Cellular Uptake and Antitumor Activity.

Kidney-type glutaminase [KGA/isoenzyme glutaminase C (GAC)] is becoming an important tumor metabolism target in cancer chemotherapy. Its allosteric inhibitor, CB839, showed early promise in cancer therapeutics but limited efficacy in in vivo cancer models. To improve the in vivo activity, we explored a bioisostere replacement of the sulfur atom in bis-2-(5-phenylacetamido-1,2,4-thiadiazol)ethyl sulfide and CB839 analogues with selenium using a novel synthesis of the selenadiazole moiety from carboxylic acids or nitriles. The resulting selenadiazole compounds showed enhanced KGA inhibition, more potent induction of reactive oxygen species, improved inhibition of cancer cells, and higher cellular and tumor accumulation than the corresponding sulfur-containing molecules. However, both CB839 and its selenium analogues show incomplete inhibition of the tested cancer cells, and a partial reduction in tumor size was observed in both the glutamine-dependent HCT116 and aggressive H22 liver cancer xenograft models. Despite this, tumor tissue damage and prolonged survival were observed in animals treated with the selenium analogue of CB839.