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Inhibitors of α‐amylase have been developed to regulate postprandial blood glucose fluctuation. The enzyme inhibition arises from direct or indirect inhibitor‐enzyme interactions, depending on inhibitor structures. However, an ignored factor, substrate, may also influence or even decide the enzyme inhibition. In this work, it is innovatively found that the difference in substrate enzymolysis modes, i.e., structural composition and concentration of α‐1,4‐glucosidic bonds, triggers the diversity in inhibitor‐enzyme aggregating behaviors and α‐amylase inhibition. For competitive inhibition, there exists an equilibrium between α‐amylase‐substrate catalytic affinity and inhibitor‐α‐amylase binding affinity; therefore, a higher enzymolysis affinity and concentration of α‐1,4‐glucosidic structures interferes the balance, unfavoring inhibitor‐enzyme aggregate formation and thus weakening α‐amylase inhibition. For uncompetitive inhibition, the presence of macromolecular starch is necessary instead of micromolecular GalG2CNP, which not only binds with active site but with an assistant flexible loop (involving Gly304‐Gly309) near the site. Hence, the refined enzyme structure due to the molecular flexibility more likely favors the inhibitor binding with the non‐active loop, forming an inhibitor‐enzyme‐starch ternary aggregate. Conclusively, this study provides a novel insight into the evaluation of α‐amylase inhibition regarding the participating role of substrate in inhibitor‐enzyme aggregating interactions, emphasizing the selection of appropriate substrates in the development and screening of α‐amylase inhibitors. [ABSTRACT FROM AUTHOR]

Aiming to design unique metallic drugs with significant therapeutic activity, in this work, mixed ligand Cu (II) complex involving 2,2′‐bipyridine and phenylalanine [Cu (bpy) (phenala.)Cl].2H2O has been fabricated and characterized using IR spectroscopy. The interaction of Cu (II) complex with CT‐DNA molecules was examined through UV–vis absorption titration plots, thermal denaturation experiments, viscosity measurements, and electrochemical studies. Cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometry measurements have been exploited to elucidate their binding style. The negative potential shift in ΔE and E1/2 values as well as the increased current density of Cu (II)/Cu(I) redox couple suggested the promoted rate of electron transfer process in presence of CT‐DNA molecules in the examined solution. Some kinetic parameters were also estimated such as the diffusion coefficient, the exchange current density, and Tafel slope values. Based on the results of these binding experiments, a groove and/or electrostatic interaction mode was expected. The antimicrobial activity of the studied Cu (II) complex was screened against a series of bacteria and fungi. An outstanding performance was shown when treating different Gram‐positive and Gram‐negative bacteria types. Moreover, an enhanced cytotoxicity behavior toward some human tumor cell lines, including MCF7, HEPG2, and HFB4, was detected with respective IC50 values of 43.02, 51.21, and >200 μM when incubated with Cu (II) complex for 72 h. These results suggest the application of [Cu (bpy) (phenala.)Cl].2H2O complex as a chemotherapeutic agent with a promising output in the drug discovery field. [ABSTRACT FROM AUTHOR]

With consumers gaining prominent awareness of health and well‐being, a diverse range of fortified or reformulated novel food is developed to achieve personalized or tailored nutrition using protein, carbohydrates, or fat as building blocks. Flavor property is a critical factor in the acceptability and marketability of fortified or reformulated food. Major food ingredients are able to interact with flavor compounds, leading to a significant change in flavor release from the food matrix and, ultimately, altering flavor perception. Although many efforts have been made to elucidate how food matrix components change flavor binding capacities, the influences on flavor perception and their implications for the innovation of fortified or reformulated novel food have not been systematically summarized up to now. Thus, this review provides detailed knowledge about the binding behaviors of flavors to major food ingredients, as well as their influences on flavor retention, release, and perception. Practical approaches for manipulating these interactions and the resulting flavor quality are also reviewed, from the scope of their intrinsic and extrinsic influencing factors with technologies available, which is helpful for future food innovation. Evaluation of food–ingredient interactions using real food matrices while considering multisensory flavor perception is also prospected, to well motivate food industries to investigate new strategies for tasteful and healthy food design in response to consumers' unwillingness to compromise on flavor for health. [ABSTRACT FROM AUTHOR]

There are many scientific reports on the interaction of the SARS‐CoV‐2 virus S protein (and its RBD) with the human ACE2 receptor protein. However, there are no reliable data on how this interaction differs from the interaction of the receptor binding domain of SARS‐CoV‐1 with ACE2, in terms of binding strength and changes in reaction enthalpy and entropy. Our studies have revealed these differences and the impact of zinc ions on this interaction. Intriguingly, the binding affinity of both RBDs (of SARS‐CoV‐1 and of SARS‐CoV‐2) to the ACE2 receptor protein is almost identical; however, there are some differences in the entropic and enthalpic contributions to these interactions. [ABSTRACT FROM AUTHOR]

Catalase (CAT) is an essential protein protecting the cell from oxidative damage by reactive oxygen species. CAT is a heme enzyme in which iron metal plays a crucial role in catalytic activity. In this research, an iron (II, III) complex ([Fe (bpy)3] [Fe (dipic)2]2.7H2O; dipic−2 = pyridine‐2,6‐ dicarboxylato and bpy = 2,2′‐bipyridine) was used to evaluate its binding interactions with bovine liver catalase (BLC) using spectroscopic and molecular docking methods. The experimental results demonstrated that the catalytic activity of BLC increased slightly and reached 106% of the initial activity. The interactions between Fe complex and BLC led to the quenching of the catalase fluorescence emission via the static quenching mechanism. Thermodynamic parameters demonstrated that the predominant interactions between catalase and Fe complex are hydrogen bond and van der Waals and the process is exothermic and enthalpy driven. The circular dichroism (CD) and synchronous fluorescence results showed that the Fe complex altered the structure and conformation of BLC. It changed the secondary structure of BLC by decreasing α‐helix and β‐sheet content. Also, the experimental data were analyzed using Multivariate Curve Resolution–Alternating Least Square (MCR‐ALS) to the resolution of measured complex spectra and estimate the number of independent chemical species. The docking results in agreement with experimental data showed that the cationic part of the complex with catalase is mainly hydrophobic and van der Waals interactions, and for the anionic part are hydrophobic, van der Waals, and hydrogen bonding. [ABSTRACT FROM AUTHOR]

Ubiquitin‐like containing PHD and ring finger (UHRF)1 and UHRF2 are multidomain epigenetic proteins that play a critical role in bridging crosstalk between histone modifications and DNA methylation. Both proteins contain two histone reader domains, called tandem Tudor domain (TTD) and plant homeodomain (PHD), which read the modification status on histone H3 to regulate DNA methylation and gene expression. To shed light on the mechanism of histone binding by UHRF2, we have undergone a detailed molecular investigation with the TTD, PHD and TTD‐PHD domains and compared the binding activity to its UHRF1 counterpart. We found that unlike UHRF1 where the PHD is the primary binding contributor, the TTD of UHRF2 has modestly higher affinity toward the H3 tail, while the PHD has a weaker binding interaction. We also demonstrated that like UHRF1, the aromatic amino acids within the TTD are important for binding to H3K9me3 and a conserved aspartic acid within the PHD forms an ionic interaction with R2 of H3. However, while the aromatic amino acids in the TTD of UHRF1 contribute to selectivity, the analogous residues in UHRF2 contribute to both selectivity and affinity. We also discovered that the PHD of UHRF2 contains a distinct asparagine in the H3R2 binding pocket that lowers the binding affinity of the PHD by reducing a potential electrostatic interaction with the H3 tail. Furthermore, we demonstrate the PHD and TTD of UHRF2 cooperate to interact with the H3 tail and that dual domain engagement with the H3 tail relies on specific amino acids. Lastly, our data indicate that the unique stretch region in the TTD of UHRF2 can decrease the melting temperature of the TTD‐PHD and represents a disordered region. Thus, these subtle but important mechanistic differences are potential avenues for selectively targeting the histone binding interactions of UHRF1 and UHRF2 with small molecules. [ABSTRACT FROM AUTHOR]

Acetylene is an important precursor in the petrochemical, plastics and electronic industries, as well as the prominent fuel for welding and metal cutting. The high flammability and explosive nature of acetylene, however hinder its safe storage and transportation. Porous materials are highly promising for acetylene storage and as they can provide strong binding interactions and an optimal pore environment. Furthermore, high selectivity and separation can be achieved for acetylene over other gases such as CO2 and small hydrocarbons. In this review, we divulge into the recent advancements and paradigms in acetylene storage and separation with a focus on porous metal‐organic frameworks (MOFs). An overview of the benchmark materials for acetylene storage and separation, along with some recent developments in the strategies to balance the trade‐off between the uptake capacity and selectivity is provided. The approaches of designing small pores and highly functionalized pore environments for strong binding with the acetylene adsorbate; along with the pore space partition, window space directed assembly and inverse CO2/C2H2 adsorption for the separation of acetylene from CO2, CH4, C2H4 and other hydrocarbons are reviewed to provide a summary and help further augment the research in this direction. [ABSTRACT FROM AUTHOR]

As the loss of free volatile compounds in aqueous protein systems is known to greatly influence the quality, and therefore the consumer acceptability, of protein-containing foods, examination of the ability of different proteins to react with volatile flavour compounds as well as the nature of the interaction are of great interest to flavour chemists. It is generally believed that the affinity of flavour to proteins is a multi-factor function related to protein source, protein conformation and stereochemistry of the flavour compound. However, the nature of protein-flavour interactions has not been explicit. Less focus has been put on plant-based proteins in comparison to animal proteins. With an increase in the use of plant-based proteins in food systems, this article provides a fundamental review of the impact protein-flavour interactions on flavour retention and release with a special emphasis on plant protein materials. Flavour-food matrix interactions have been examined with a focus on how they influence flavour perception. Current knowledge on methodologies involved in protein-flavour binding studies, binding mechanisms and factors affecting the interaction have been discussed. The implication of protein-flavour interaction on protein functionality specifically protein thermal gelation properties has also been considered. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Front Cover: New Paradigms in Porous Framework Materials for Acetylene Storage and Separation (Eur. J. Inorg. Acetylene separation, Acetylene storage, Binding interactions, Metal-organic frameworks, Selectivity Keywords: Acetylene separation; Acetylene storage; Binding interactions; Metal-organic frameworks; Selectivity EN Acetylene separation Acetylene storage Binding interactions Metal-organic frameworks Selectivity 4496 4496 1 11/29/21 20211125 NES 211125 B The Front Cover b shows how humans may benefit from acetylene naturally present in the solar system during astronavigation. [Extracted from the article]

A series of copper(II) complexes containing 6‐methyl‐2‐oxo‐1,2‐dihydroquinoline‐3‐carboxaldehyde‐derived Schiff bases have been synthesized and characterised using various analytical and spectroscopic techniques. X‐ray crystallographic analysis confirmed the true coordinating nature of ligands with copper ion. The ligands exhibited ONS tridentate neutral and monobasic coordination. The spectroscopic results evidenced the interaction of the ligands and their copper(II) complexes with nucleic acid/serum albumin. Further, the complexes showed significant activity against human skin cancer cell line (A431) and less toxicity against human keratinocyte cell line (HaCaT). Acridine orange/propidium iodide dual staining studies indicated that the major cause of A431 cell death was through necrosis. By comparing the biological activity of all the ligands, Cu(II) complexes and standard (cisplatin), complex [Cu(H‐6MOQtsc‐Ph)(H2O)]⋅NO3 (4) exhibited better activity than others, the activity being arranged as follows: 4 > 1 > cisplatin > 3 > 2. The work focuses on the synthesis and biological evaluations of heterocyclic Schiff bases and their copper(II) metallates. [ABSTRACT FROM AUTHOR]