Biomolecular interaction

MRI CAs meet a variety of biomolecules in physiological environments, and may interact with proteins, human serum albumin (HSA), enzymes, and receptors. The binding of CAs to HSA is widely studied because it is the most abundant protein in blood plasma. HSA has a molecular weight of 66 kDa, a concentration of approximately 0.64 mM, and with two major binding sites, which are subdomains of IIA and III A [63]. 

Receptor-induced magnetization enhancement (RIME) describes the binding of CAs to biomolecules, such as proteins or receptors. This leads to an increase in the concentration and retention time of CAs in a particular region. It also results in an increase in tr and has a tremendous effect on increasing the relaxivity [64]. 

The binding affinity (Kp,) (Equation 10.14) and relaxivity (rj) of the adducts that form between complexes and macromolecules can be measured by the proton relaxation enhancement (PRE) method [65, 66], PRE is based on the titration of complexes against the binding substrate of macromolecules, such as HSA. The binding of complexes to HSA influences the XR, Tm, Tie, and Tim of complexes. If a Gd complex (GdL) binds to HSA, then adducts form and r is usually higher than ri. 

Ibuprofen and warfarin are ligands that strongly bind to the sub-domains IIA and IIIA, respectively, of HSA. The identity of the HSA binding site can be determined through competitive binding assays with known binding substrates, such as ibuprofen, warfarin, bilirubin, linolenic acid, and 1,3,5-triiodobenzoic acid. 

HSA binding not only interferes with the inner-sphere water molecules, but also the outer-sphere. DOTP( 1,4,7,10-tetraazacyclododecane-N, N , N , A -tetrakis(methylenephosphonic acid) derivatives have no inner-sphere water molecule, and rely on the outer-sphere mechanism. This property allows the study of how HSA binding sites affect relaxivity, which shows that differences in r are solely due to the nature of the binding sites [77,78]. 

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Weak Forces Maintain Biological Structure and Determine Biomolecular Interactions... 

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The interaction between c Fusarium moniliforme and PGIP from Phaseolus vulgaris L. was investigated using a biosensor technique based on sur ce plasmon resonance (BIAlite). This new analytical system provides information on the strength and the kinetics of biomolecular interactions. 

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Optical methods are a perfect tool to characterize interaction processes between a sensitive chemical or bio polymer layer and analytes1. Time-resolved measurements of this interaction process provide kinetic and thermodynamic data. These types of sensors allow the monitoring of production processes, quantification of analytes in mixtures and many applications in the area of diagnostics, biomolecular interaction processes, DNAhybridization studies and evenprotein/protein interactions2,3. 

So far, optical biosensors have been mostly used in research laboratories for biomolecular interaction analysis in which the binding interactions between a ligand immobilized at the sensor surface and its molecular partner in a solution passed over this surface are studied. 

Sasuga, Y., Tani, T., Hayashi, M., Yamakawa, H., Ohara, O., and Harada, Y. (2006) Development of a microscopic platform for real-time monitoring of biomolecular interactions. Genome Res. 16, 132-139. 

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Selective agonist binding of AMPA and kainate receptors. P21, Biomolecular Interactions, Molecular Graphics and Modelling Society, Bristol UK, 3-5 April. 

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