Briefly, 2-(4-Acetamido-2-sulfanilamide) chitosan, which is a chitosan water-soluble derivative, with molecular weights of 200, 350, and 600 kDa, was successfully synthesized. The immobilization of ficin, papain, and bromelain was carried out by complexation with these polymers. The interaction mechanism of 2-(4-acetamido-2-sulfanilamide) chitosan with bromelain, ficin, and papain was studied using FTIR spectroscopy. It was found that the hydroxy, thionyl, and amino groups of 2-(4-acetamido-2-sulfanilamide) chitosan were involved in the complexation process. Molecular docking research showed that all amino acid residues of the active site of papain formed hydrogen bonds with the immobilization matrix, while only two catalytically valuable amino acid residues took part in the H-bond formation for bromelain and ficin. The spectral and in silico data were in good agreement with the catalytic activity evaluation data. Immobilized papain was more active compared to the other immobilized proteases. Moreover, the total and specific proteolytic activity of papain immobilized on the carrier with a molecular weight of 350 kDa were higher compared to the native one due to the hyperactivation. The optimal ratio of protein content (mg × g −1 of carrier), total activity (U × mL−1 of solution), and specific activity (U × mg−1 of protein) was determined for the enzymes immobilized on 2-(4-acetamido-2-sulfanilamide) chitosan with a molecular weight of 350 kDa.

Cell fate engineering technologies are critically important for basic and applied science, yet many protocols for direct cell conversions are still unstable, have a low yield and require improvement. There is an increasing need for a data aggregator containing a structured collection of protocols -  preprocessed, verified, and represented in a standardized manner to facilitate their comparison, and providing a platform for the researchers to evaluate and improve the protocols.   We developed CFM (cell fate mastering), a database of experimentally validated protocols for chemical compound-based direct reprogramming and direct cell conversion. The current version of CFM contains 169 distinct protocols, 113 types of cell conversions, and 158 small molecules capable of inducing cell conversion. CFM allows stem cell biologists to compare and choose the best protocol with high efficiency and reliability for their needs. The protocol representation contains PubChem CIDs and Mechanisms Of Action (MOA) for chemicals, protocol duration, media , and yield with a comment on a measurement strategy. Ratings of the protocols and feedback from the community will help to promote high-quality and reproducible protocols. We are committed to a long-term database maintenance strategy. The database is currently available at https://cfm.mipt.ru}{cfm.mipt.ru

Исследован механизм воздействия УФ-излучения на трипсин, иммобилизованный на матрице среднемолекулярного (200 кДа) и высокомолекулярного (350 кДа) хитозанов. Установлено, что ферментативная активность молекул иммобилизованного трипсина под воздействием УФ-излучения практически не подвержена изменению. Выдвинуто предположение о фотопротекторном эффекте матрицы хитозана. Выявлено, что при дозе 6040 Дж/м2 происходят изменения в структуре белкового комплекса, связаные с варьированием количества неупорядоченных структур и β-слоев в молекуле фермента, –СОО– колебаниями аминокислот, проявляющиеся в снижении активности препарата.

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