China
Africa
Explore chapters and articles related to this topic
Imaging of Beta-Receptors in the Heart
Published in Robert J. Gropler, David K. Glover, Albert J. Sinusas, Heinrich Taegtmeyer, Cardiovascular Molecular Imaging, 2007
Jeanne M. Link, John R. Stratton, Wayne C. Levy, Jeanne Poole, James H. Caldwell
Interpretable β-AR imaging requires a radiolabeled tracer that binds rapidly and tightly (slow koff) to the receptor. However, the binding cannot be so tight that the tracer is irreversibly bound to the receptor nor so rapid that it is first-pass extracted and thus is a measure of delivery by blood flow. A radiotracer antagonist with a KD in the nanomolar range usually meets these requirements (16). As mentioned, the radiotracer must be specific for the β-AR and not bind to other receptors or be taken up nonspecifically in the heart. The image of a high specific activity bound radiopharmaceutical may be sufficient to give an indication of the regional distribution of the receptor within the heart but, by itself, does not provide individual values for the receptor density or affinity. The measured product of receptor density and KD is referred to as the binding potential. It is more useful to know the density of receptor concentration because that is the number of available receptors and is a measure of the potential responsiveness of the system. KD may or may not be an important parameter to determine from imaging, depending on whether or not it changes as part of the disease process. For mixed agonist/antagonist ligands, the starting assumption must be that it does change with disease, but there is little information in humans as yet.
Photo excitation of silver ions during the synthesis of silver nanoparticles modify physiological, chemical, and biological properties
Published in Particulate Science and Technology, 2023
Anila Sajjad, Sajjad Hussain Bhatti, Muhammad Zia
Because of the chelation of ferrous ions, the retardation of metal-catalyzed oxidation has major anti-oxidative effects. Iron stimulates lipid peroxidation by Fenton’s reaction. Ferrozine generates magenta complexes when it reacts with Fe2+. The presence of chelating substances disrupts the formation of complexes, resulting in a decrease in complex absorbance and color. That indicates increased metal chelating activity (Gaur et al. 2018). A metal-chelating analysis was used to evaluate the chelation potential of photo-excited SNPs. Following DPPH results, DL-SNPs had the most significant chelation capacities with 48.90%, followed by Y-SNPs with 46.54% (Table 3). The results also indicate that SNPs have efficient ligand binding potential for chelating metal ions, inhibiting the formation of hydroxyl radicals by Fenton’s reaction. The smaller size and greater surface area of DL-SNPs and Y-SNPs explain their enhanced activity in the metal chelation test. As the surface area increases, the number of atoms on the surface increases, resulting in significant antioxidant responses (Sritong, Chumsook, and Siri 2018).
Toxicity, monitoring and biodegradation of organophosphate pesticides: A review
Published in Critical Reviews in Environmental Science and Technology, 2019
Gurpreet Kaur Sidhu, Simranjeet Singh, Vijay Kumar, Daljeet Singh Dhanjal, Shivika Datta, Joginder Singh
X-ray diffraction is considered to be a reliable technique for evaluating and determining the working of metal ligand and their apparent binding potential which can aid in developing advance sensors (Gong et al., 2012). [R3P=O—Mn+] moieties in a study, where (R = alkyl, aryl and M = any metal), the mean length of P=O bond in P=O—Mn+ interaction was found to 1.48 Å and the mean length of M—O was found to be 2.33 Å. These structure mimics the fragments of deprotonated acid in which three atoms are bound to one metal present in the center (Kumar et al., 2013). The [-P=OMe(OR)-] could be assumed to be resembling (CH2)2 structure. The motif is reliable as the sample gets degraded due to the hydrolysis of -OR group. On studying the interaction via XRD-Spectrophotometer, it revealed that metal ions of Fe(III), Al(III), Co(II) and Zn(II) forms the complexes with methylphosphonic acid which forms M-(CH3PO3)3·3H2O, and aminomethylphosphonic acid forms M-OH(NH3CH2PO3)2·H2O complex. X-ray aids in deciphering the octahedral structure of the complexes of N-phosphonomethylglycine having M-OH(-OOC–CH2–NH2+–CH2–PO32−)·2.25 H2O as the proposed structural formula. X-ray study representing that metal ions concerned in octahedral structure (Kaur et al., 2018).
Zinc(II) derivatives of N, O containing Schiff bases: synthesis, characterization, computational and biological studies
Published in Journal of Coordination Chemistry, 2023
Saadia Batool, Anham Zafar, Muhammad Athar, Mehwish Mehmood, Muhammad Nawaz Tahir, Ihsan-Ul Haq, Sayed Sikander Azam
Computational studies are usually carried out to estimate the antimicrobial potential of compounds by exploring their possible binding patterns with the selected receptor enzyme and to envisage the most probable intermolecular complex formed between receptor enzyme and inhibitor compound [47]. Molecular docking studies against the receptor enzyme E. coli (β-ketoacyl-(acyl-carrier-protein) synthase III (ecKAS-III) are conducted and the receptors are selected as target based on antibacterial activity data. Information regarding binding sites is obtained from reported crystal structures of target receptor enzyme E. coli (β-ketoacyl-(acyl-carrier-protein) synthase III available in protein data bank with assigned PDB code-2Q85. Compounds exhibiting strong antibacterial potential against tested bacterial strains showed a higher GOLD fitness score, presented in Table 8. Among free Schiff bases, I1 exhibited largest ligand-binding potential to synthase III enzyme by acquiring a GOLD score of 51.5 which is attributed to its methoxy and nitro functional groups [48]. The results of docking studies when compared with the antibacterial activity data further revealed that 7, the most active antibacterial agent against target enzyme E. coli (β-ketoacyl-(acyl-carrier-protein) synthase III (ecKAS-III), got the highest GOLD fitness score of 60.2 exhibiting a strong ligand-receptor affinity. Free Schiff base I7 shows a minimum score of 46.7 representing a weaker binding affinity. Compounds 2 and 3 also demonstrated significant binding affinity with GOLD scores of 57.7 and 53.3, respectively. The 3-D interaction for 7 and the 2-D interactions for I7 with amino acid residues inside the active site of target enzyme are shown in Figures 6, 7, and 8, respectively. The specific amino acid residues in the active-site pocket of the target protein predominantly involved Gly227, Ser228, Leu217, Ser49, Pro220, Pro110, Leu289, Pro218, Val290, Ala263, Gly265, Asn232, Ile109, Thr9, Asn225, and Arg213 (Figure 8). Compounds 7 and 2 have potential to act as promising “lead compounds” against synthase III enzyme, also evident from their significant in-silico binding interaction with target enzyme. The complexes show more bonding with amino acid residues than the ligands, attributed to their significant electrostatic H-bonding interaction. Moreover, the docking analysis of the compounds illustrates their interaction with amino acid residues of protein that defined their effectiveness as an enzyme inhibitor.