Synthesis and characterization of metal complex amino acid using spectroscopic methods and theoretical calculation

Binding mechanism of metal ions (Ca2+, Cu2+ and Mg2+) with tetrapeptide FFDR: A combined experimental and quantum chemistry approach

A previous study demonstrated that a tetrapeptide FFDR derived from coix seed possesses antioxidant properties. In continuation of the study, Density Functional Theory (DFT) was employed to investigate the molecular-level complexation behaviour of FFDR with Ca2+, Cu2+, and Mg2+. DFT predictions were validated using spectroscopy and cellular model. The electronic properties revealed that Mg-FFDR, with its lower energy gap (1.733 eV), exhibits higher reactivity compared to Ca-FFDR which displayed higher stability (8.180 eV). The Quantum Theory of Atoms in Molecules (QTAIM) showed positive Laplacian values for all metal‑oxygen bonds, indicating the presence of coordination bonds characteristic of closed-shell interactions. Results from 1H NMR spectra revealed J-coupling patterns consistent with metal coordination for Mg and Ca-peptide complexes. FTIR spectra displayed distinct changes in the vibrational frequencies of functional groups involved in metal binding for all complexes. Both Mg-FFDR and Ca-FFDR demonstrated significant ROS scavenging activities, and enhanced SOD and CAT activities in HepG2 cells. These findings serve as a baseline for the rational design of metal-peptide complexes as functional foods or nutraceuticals.

Simplified Biochemical Analysis Using p‑Block Metals and Their Compounds with SilverSurface Enhancement from the Point of View of Electronic Structure

This mini-review presents recent trends in the field of surface-enhanced spectroscopies, which are increasingly gaining ground for biomolecule detection. The paper discusses the role of electromagnetic and chemical bonding mechanisms for an explanation of Raman scattering and fluorescence enhancement. The charge transfer (CT) effect, which is involved in the chemical mechanism, plays an important role in changing the polarizability and is decisive in enhancing certain Raman scattering bands and fluorescence emission. The CT effect is determined by the band structure and the energy of the excitation radiation by which photoelectrons and holes with different energies are generated. Here we analyze the changes in the band structure of silver by adding p-block metals as well as the possibility to control CT and to enhance specific Raman bands through their engineering.

Thermodynamic parameters of phenylglycine interaction with UO22+, La3+ and Zr4

Phenylglycine interactions with (UO₂²⁺, La³⁺ and Zr⁴⁺) transition metal ions were studied at different ionic strengths and different temperature degrees applying Bjerrum's method. The work determine and discuss both the thermodynamic stabilities and the degree of interactions [Formula: see text]. Also the work calculate and discuss the thermodynamic parameters of interactions of phenylglycine with (UO₂²⁺, La³⁺ and Zr⁴⁺). The variables that govern the interaction between phenylglycine and the metal ions under investigation were related to the nature of the amino acid reactive species as well as to the nature of M⁺ such as the valence and radius of the ion. It was observed that reactions between the M⁺ and L^- were the most likely to occur. It was determined that the pH values affect the degree of complex formation [Formula: see text] as well as the production of various reactive spices. When the range of degree of interaction was more than 0.5 and less than 1.15, forming 1:1 stoichiometric complex. Additionally, it was shown that the stability of the complexes produced between phenylglycine and M^Z+ increased in the subsequent order, which was in good accord with the Irving-Williams order.

The enhanced dewaterability of sludge by a starch-based flocculant combined with attapulgite

Coagulation/flocculation is one of the most widely used and cost-effective pretreatment methods for improving the dewaterability of sludge. In this study, a cationic modified starch-based flocculant (St-CTA) in conjunction with a popular clay, attapulgite (ATP), was used for the conditioning of waste-activated sludge. The dewatering properties, including the filter cake moisture content, filtration specific resistance, capillary suction time, filtration rate and compressibility coefficient, were measured and compared by varying the doses of St-CTA and ATP. By combination of the apparent dewatering performance and the changes in the contents and distributions of the extracellular polymeric substance (EPS) fractions and components, sludge flocs, and microstructures of sludge cakes, the dewatering mechanisms were discussed in detail. St-CTA in conjunction with ATP can exhibit an enhanced dewaterability of sludge and the water content in final sludge cake can be stably reduced below 80% owing to the synergistic effects of St-CTA and ATP. In addition to the efficient charge neutralization of St-CTA, ATP not only acts as a skeleton builder in the sludge dewatering process which makes the sludge flocs more compact and improves the filterability and permeability, but also tightly interacts with the proteins in EPS of the sludge which reduces the protein content and further enhances the dewatering effect. This study provides an economical, green, and effective way to further improve the dewaterability of sludge.

Thermodynamic Parameters of Phenylglycine Interaction with UO22+, La3+ and Zr4+.. [DOI: 10.21203/rs.3.rs-1881732/v2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The interactions between phenylglycine and some transition metal ions (UO22+,La3+ and Zr4+) were studied at three ionic strengths [(µ = 0.05, 0.10 and 0.15) M KNO3] and three temperatures [(25, 35 and 45) ºC] in aqueous media by using Bjerrum’s potentiometric technique. The stoichiometric and thermodynamic stability constants as well as the degree of complexation for all studied systems (\(\stackrel{-}{\text{n}}\)) were determined and discussed. The standard thermodynamic parameters (Δ pKº and Δlog Kº) and the thermodynamic parameter differences (ΔGº, ΔΔGº, ΔHº, ΔΔHº, ΔSº, and ΔΔSº) were calculated for all possible reactions. Advanced discussions of these functions as well as the factors that may control the complexation processes from the thermodynamic point of view have been reported.

DFT study on the structural and chemical properties of Janus kinase inhibitor drug Baricitinib

Baricitinib is a small molecule used to treat moderate to severe rheumatoid arthritis (RA) in adults. It is an inhibitor of Janus kinase 1 and 2 (JAK1 and JAK2). It has also been repurposed as a potential treatment for Covid 19. The current study has been carried out to understand the structural and chemical properties of this molecule. The molecule is optimized by using density functional theory (DFT) method. The DFT calculations are performed using Gaussian 09 W software package. The bond lengths and bond angles between atoms in the molecules are investigated. The intramolecular interaction within the molecule is identified using the natural bond orbital (NBO) study. The atom in molecule (AIM) study is performed using Multiwfn software. All the calculations are performed at B3LYP /6311G++ (d, p) level of theory. The molecular parameters, such as first-order hyperpolarizability, HOMO-LUMO energy gap, global electrophilicity index, dipole moment, chemical potential, hardness, ionization energy and electron affinity are determined from the calculation. The molecular docking analysis of Baricitinib is also carried out against different target proteins such as 6VSB, 6W9C and 6LU7.