Explore chapters and articles related to this topic
Immunological Approaches
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Deborah E. Dixon, Susan J. Steiner, Stanley E. Katz
The basis of the immunoassay for antibiotics depends upon the binding of the antibiotic with a specific antibody in a reversible reaction: The reaction is an equilibrium reaction and continues until the concentration of antigen in both the free state and the complex are constant [4]. The antiserum is one of the most important reagents in the immunoassay. It determines the specificity and to some extent the sensitivity. Because most antibiotics are relatively small molecules (molecular weights less than 400), they must be complexed with carrier proteins, such as bovine serum albumin, to create an immunogenic reagent. This complex is used to invoke the immune response and the development of antibodies. The specificity of the antibodies developed is dependent upon the haptenic structure. In general, immune reactions are highly specific. Any given population of antibody molecules will (usually) have different affinities for those ligands, whose structures differ in a subtle fashion. As a rough rule of thumb, the ability of antibodies to distinguish molecules is comparable to the specificity of enzymes.
The Involvement of Adenylyl Cyclase And Cyclic Amp-Dependent Protein Kinases in Luteinizing Hormone Actions
Published in Mario Ascoli, Luteinizing Hormone Action and Receptors, 2019
Mary Hunzicker-Dunn, Lutz Birnbaumer
The reaction denoted above is a reversible equilibrium reaction. As we have previously discussed, subunit dissociation and reassociation rates are dependent not only upon the cyclic AMP concentration in contact with the enzymes, but also upon their interactions with ATP and their states of phosphorylation. In addition, the equilibrium position of this reaction as well as the activity of the catalytic subunit is affected by one or more heat-stable inhibitor (I) proteins which interact with the catalytic subunit, rendering the CI complex catalytically inactive and incapable of recombining with the regulatory subunit.221,222
General Techniques for Solving Equilibrium Problems
Published in Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk, Survival Guide to General Chemistry, 2019
Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk
For the following three equilibria, show the equilibrium reaction equation to include heat as a reactant or product; then state which direction the equilibrium will shift for each of the following induced changes: (1) Hydrogen gas is removed; (2) Carbon monoxide is added; (3) Temperature is increased; (4) Temperature is decreased.
Synergistic Effect of Self-Assembled Curcumin and Piperine Co-Loaded Human Serum Albumin Nanoparticles on Suppressing Cancer Cells
Published in Drug Development and Industrial Pharmacy, 2020
Hossein Abolhassani, Maryam Sadat Safavi, Somayeh Handali, Mohsen Nosrati, Seyed Abbas Shojaosadati
The investigation of protein secondary structure in the nanoparticulate form is a crucial matter in the assessment of drug delivery system potency. Albumin NPs could transport anticancer drugs to tumor cells through targeted drug delivery owing to the existence of some albumin receptors on cancer cells surface such as GP60 (glycoprotein 60-kDa) and SPARK (secreted protein acidic and rich in cysteine) [8,43]. In this study, CD spectroscopy was employed to find the secondary structural change of albumin molecules in CUR-PIP-HSA-NPs. As shown in Figure 2, a slight change in albumin configuration occurred alongside the synthesis of NPs by the self-assembly method compared to the CD spectra of control. A 6% change in α-helix content was determined (Table 1). HSA molecules have a few hydrophobic regions buried in their structure, and by adding a reducing agent, some disulfide bridges are cleaved in a chemical equilibrium reaction which makes a minor structural change in the molecules [45]. Moreover, the addition of hydrophobic drugs leads to the formation of some hydrophobic interactions resulting in an increase in the random coil content. Meanwhile, the capability of targeting delivery of drugs by CUR-PIP-HSA-NPs formulation through engagement with cancer cells receptors could be inferred on account of the slight change in albumin structure.
Design and characterization of calcium-free in-situ gel formulation based on sodium alginate and chitosan
Published in Drug Development and Industrial Pharmacy, 2018
Linda Belhadji, Abdelkader HadjSadok, Nadji Moulai-Mostefa
Chitosan is a linear and flexible copolymer; it consists of β(1→4) linked with 2-acetamido-2-deoxy-β-d-glucopyranose and 2-amino-2-deoxy-β-d-glucopyranose. This polysaccharide is obtained by N-deacetylation of chitin which is extracted from the carapace of crustaceans [25]. Chitosan particles are insoluble in aqueous solution at neutral pH but dissolves in acidic medium by protonation of their amino groups, according to the equilibrium reaction: (26]. Other interactions can arise such as hydrogen bonds and hydrophobic ones between acetylated units of chitosan [27]. A physical hydrogel may then be formed such as entangled hydrogel. However, it has been shown that this type of gel is limited by its lack of mechanical strength and its tendency to dissolve. Because of its nontoxicity, good stability, and biocompatibility [28], chitosan has been the subject of much research as biomaterial in the development of drug delivery systems. It was used in various medical applications as wound dressings, contact lenses, and encapsulation systems [29]. Also, chitosan hydrogels have been exploited for the delivery of biologically active molecules; their formation, according to the in-situ gelling process, has allowed their integration into several other routes of administration (ocular, nasal, and parenteral), enhancing the protection of drugs and cells against the hostile environment [29]. It was also used as mucoadhesive gels allowing intimate contact with the absorbing mucosa of the stomach thus improving absorption and bioavailability [30].
Toxic uranium contamination in groundwater of Thoothukudi district, India: Evaluation of health risks using the geochemical and statistical approach
Published in Toxin Reviews, 2023
Velayutham Raja, Mallanpillai Ananthakrishnan Neelakantan
The PHREEQC (pH-REdox-EQuilibrium Code) geochemical model is used to simulate the equilibrium reaction between groundwater and subsurface minerals (Safonov et al. 2021). In the present study, computer programs were used to simulate the ionic composition of the groundwater samples (saturation indices - SI). The degree of saturation is calculated as the Saturation Index by the following Equation (2) (Santhanam et al. 2021) sp - solubility constant; IAP - Ion activity product. The saturation indices (SI) values represent the under-saturation (<0), saturation (=0), and super-saturation (>0) (Pande et al.2020).